Android快速入门-----用户界面（下）UI布局，Android应用练习

一、UI布局

1、常用UI布局

（1）LinerLayout

线性布局：用来控制其子View以水平或垂直方式展开显示

（2）理解LinearLayout权重

（3）创建项目搭建上面的界面

1）创建项目工程

2）创建新的布局

liner_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="To" >
    </EditText>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Subject" >
    </EditText>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:hint="Message" 
        android:gravity="top"
        >
    </EditText>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Reset" 
            />
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Send"
             />
    </LinearLayout>
</LinearLayout>

3）修改MainActivity

package com.itzheng.l03_layout;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends Activity {
    
    
	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.liner_layout);
	}
}

（4）RelativeLayout相对布局

1）创建布局实现上述案例

对应的页面的代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <TextView
        android:id="@+id/et_relative_msg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:hint="Message" />
    <Button 
        android:id="@+id/btn_relative_ok"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="OK"
        android:layout_below="@+id/et_relative_msg"
        android:layout_alignRight="@+id/et_relative_msg" />
    <Button 
        android:id="@+id/btn_relative_cancle"
         android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Cancle"
		android:layout_alignTop="@id/btn_relative_ok"
		android:layout_toLeftOf="@id/btn_relative_ok" 
		android:layout_marginRight="10dp"       
        />
</RelativeLayout>

（5）FrameLayout

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1）创建布局

2）完成上述案例当中的样式

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:layout_width="280dp"
        android:layout_height="280dp"
        android:background="#33ffff"
        android:layout_gravity="center"
        
         />
    <TextView
        android:layout_width="240dp"
        android:layout_height="240dp"
        android:background="#33aaff"
        android:layout_gravity="center"
        
         />
    <TextView
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:background="#33ccff"
        android:layout_gravity="center"
        
         />
    <TextView
        android:layout_width="160dp"
        android:layout_height="160dp"
        android:background="#3399ff"
        android:layout_gravity="center"
        
         />
     <TextView
        android:layout_width="120dp"
        android:layout_height="120dp"
        android:background="#3366ff"
        android:layout_gravity="center"
        
         />
     <TextView
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:background="#3311ff"
        android:layout_gravity="center"
        
         />
     <TextView
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:background="#3300ff"
        android:layout_gravity="center"
        
         />
     
     <!-- 
     	gravity:控制的是当前视图的内容/子视图
     	layout_gravity:控制当前视图自己
      -->
     

</FrameLayout>

2、常用视图标签的属性

（1）属性的划分

（2）常用的基本属性

（3）内边距与外边距

内边距属性

（4）创建新的视图

实现上述的视图

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <EditText
        android:id="@+id/editText1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:hint="Messsage"
        android:paddingLeft="20dp"
        />
    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/editText1"
        android:layout_below="@id/editText1"
        android:layout_marginTop="20dp"
        android:text="OK" />
</RelativeLayout>

（5）同方向对齐与反方向对齐

（6）相对父视图定位

3、ListView

（1）Adapter

（2）ListView和ArrayAdapter

实现上述效果

1）创建项目

2）页面搭建

<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/lv_main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
</ListView>

3）创建新的页面

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</TextView>

4）实现上述样式

修改item_array_adapter.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:textSize="20sp"
    android:gravity="center_vertical"
     >
</TextView>

修改activity_main.xml

<ListView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/lv_main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

</ListView>

修改MainActivity

package com.itzheng.l03_listview;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {
    
    
	
	private ListView lv_main;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		lv_main = (ListView)findViewById(R.id.lv_main);
		
		//准备集合数据
		String[] data = {
    
    "A","B","C","D","E","F","H","I","J","K","L","M"};
		//准备ArrayAdaper对象
		ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.item_array_adapter,data);
		//设置Adatper显示列表
		lv_main.setAdapter(adapter);
		
	}
}

（3）ListView+SimpleAdapter

a、准备一些图片

复制到

b、更改上述的MainActivity

public class MainActivity extends Activity {
    
    
	
	private ListView lv_main;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		lv_main = (ListView)findViewById(R.id.lv_main);
		
		//准备集合数据
		List<Map<String,Object>> data = new ArrayList<Map<String,Object>>();
		
		Map<String,Object> map = new HashMap<String, Object>();
		
		map.put("icon", R.drawable.f1);
		map.put("name", "name--1");
		map.put("content", "content--1");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f2);
		map.put("name", "name--2");
		map.put("content", "content--2");
		
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f3);
		map.put("name", "name--3");
		map.put("content", "content--3");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f4);
		map.put("name", "name--4");
		map.put("content", "content--4");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f5);
		map.put("name", "name--5");
		map.put("content", "content--5");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f6);
		map.put("name", "name--6");
		map.put("content", "content--6");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f7);
		map.put("name", "name--7");
		map.put("content", "content--7");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f8);
		map.put("name", "name--8");
		map.put("content", "content--8");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f9);
		map.put("name", "name--9");
		map.put("content", "content--9");
		data.add(map);
		
		map = new HashMap<String, Object>();
		map.put("icon", R.drawable.f10);
		map.put("name", "name--10");
		map.put("content", "content--10");
		
		data.add(map);
		
		//map对象当中key的数组，用于得到对应的value
		String[] from = {
    
    "icon","name","content"};
		
		//Item布局文件中子view的id的数组
		int[] to = {
    
    R.id.iv_item_icon,R.id.tv_item_name,R.id.tv_item_content};
		//准备SimpleAdapter对象
		SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item_simple_adapter, from, to);
		
		//设置Adatper显示列表
		
		lv_main.setAdapter(adapter);
		
	}
}

c、创建布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
    <ImageView
        android:id="@+id/iv_item_icon"
        android:layout_width="70dp"
        android:layout_height="70dp"
        android:src="@drawable/f1" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" 
        android:gravity="center_vertical"
        android:layout_marginLeft="10dp"
        >
        <TextView
            android:id="@+id/tv_item_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="TextView" />
        <TextView
            android:id="@+id/tv_item_content"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="TextView" />
    </LinearLayout>
</LinearLayout>

（4）ListView+BaseAdapter

a、创建实体类ShopInfo

package com.itzheng.l03_listview; 
/*
 * 每行的Item的数据信息分装类
 */
public class ShopInfo {
    
    
	private int icon;
	private String name;
	private String content;
	public ShopInfo(int icon, String name, String content) {
    
    
		this.icon = icon;
		this.name = name;
		this.content = content;
	}
	public int getIcon() {
    
    
		return icon;
	}
	public void setIcon(int icon) {
    
    
		this.icon = icon;
	}
	public String getName() {
    
    
		return name;
	}
	public void setName(String name) {
    
    
		this.name = name;
	}
	public String getContent() {
    
    
		return content;
	}
	public void setContent(String content) {
    
    
		this.content = content;
	}
	@Override
	public String toString() {
    
    
		return "ShopInfo [icon=" + icon + ", name=" + name + ", content="
				+ content + "]";
	}
}

b、修改MainActivity

public class MainActivity extends Activity {
    
    
	private ListView lv_main;
	private List<ShopInfo> data = null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		lv_main = (ListView) findViewById(R.id.lv_main);
		// 准备集合数据
		data = new ArrayList<ShopInfo>();
		data.add(new ShopInfo(R.drawable.f1, "name---1", "content---1"));
		data.add(new ShopInfo(R.drawable.f2, "name---2", "content---2"));
		data.add(new ShopInfo(R.drawable.f3, "name---3", "content---3"));
		data.add(new ShopInfo(R.drawable.f4, "name---4", "content---4"));
		data.add(new ShopInfo(R.drawable.f5, "name---5", "content---5"));
		data.add(new ShopInfo(R.drawable.f6, "name---6", "content---6"));
		data.add(new ShopInfo(R.drawable.f7, "name---7", "content---7"));
		data.add(new ShopInfo(R.drawable.f8, "name---8", "content---8"));
		data.add(new ShopInfo(R.drawable.f9, "name---9", "content---9"));
		data.add(new ShopInfo(R.drawable.f10, "name---10", "content---10"));
		// 准备SimpleAdapter对象
		MyAdapter adapter = new MyAdapter();
		// 设置Adatper显示列表
		lv_main.setAdapter(adapter);
	}
	class MyAdapter extends BaseAdapter {
    
    
		// 返回集合数据的数量
		@Override
		public int getCount() {
    
    
			return data.size();
		}
		// 返回指定下标对应数据对象
		@Override
		public Object getItem(int position) {
    
    
			// TODO Auto-generated method stub
			return data.get(position);
		}
		@Override
		public long getItemId(int position) {
    
    
			// TODO Auto-generated method stub
			return 0;
		}
		// 返回指定下标所对应的item的View对象
		// position:下标
		// convertView:
		// parent:ListView对象
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
    
    
			// 加载item的布局，得到View对象(得到XML页面的对象)
			View view = View.inflate(MainActivity.this,
					R.layout.item_simple_adapter, null);
			// 根据position设置对应的数据
			// 得到当前行的数据对象
			ShopInfo shopInfo = data.get(position);

			// 得到子View对象，得到XML页面上的子View对象
			ImageView imageView = (ImageView) view
					.findViewById(R.id.iv_item_icon);
			TextView name = (TextView) view.findViewById(R.id.tv_item_name);
			TextView contentTV = (TextView) view.findViewById(R.id.tv_item_content);
			// 设置数据
			imageView.setImageResource(shopInfo.getIcon());
			name.setText(shopInfo.getName());
			contentTV.setText(shopInfo.getContent());
			return view;
		}
	}
}

运行效果显示

c、上述方式效率不高（改进上述方式）

如果没有复用视图对象而不断的产生新的视图对象，会内存溢出，提前判断使用复用视图对象，并使用convertView来创建视图，添加判断以后只加载六次布局

package com.itzheng.l03_listview;
public class MainActivity extends Activity {
    
    

	private ListView lv_main;

	private List<ShopInfo> data = null;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		lv_main = (ListView) findViewById(R.id.lv_main);

		// 准备集合数据

		data = new ArrayList<ShopInfo>();

		data.add(new ShopInfo(R.drawable.f1, "name---1", "content---1"));
		data.add(new ShopInfo(R.drawable.f2, "name---2", "content---2"));
		data.add(new ShopInfo(R.drawable.f3, "name---3", "content---3"));
		data.add(new ShopInfo(R.drawable.f4, "name---4", "content---4"));
		data.add(new ShopInfo(R.drawable.f5, "name---5", "content---5"));
		data.add(new ShopInfo(R.drawable.f6, "name---6", "content---6"));
		data.add(new ShopInfo(R.drawable.f7, "name---7", "content---7"));
		data.add(new ShopInfo(R.drawable.f8, "name---8", "content---8"));
		data.add(new ShopInfo(R.drawable.f9, "name---9", "content---9"));
		data.add(new ShopInfo(R.drawable.f10, "name---10", "content---10"));

		// 准备SimpleAdapter对象
		MyAdapter adapter = new MyAdapter();
		// 设置Adatper显示列表
		lv_main.setAdapter(adapter);

	}

	class MyAdapter extends BaseAdapter {
    
    

		// 返回集合数据的数量
		@Override
		public int getCount() {
    
    
			return data.size();
		}

		// 返回指定下标对应数据对象
		@Override
		public Object getItem(int position) {
    
    
			// TODO Auto-generated method stub
			return data.get(position);
		}

		@Override
		public long getItemId(int position) {
    
    
			// TODO Auto-generated method stub
			return 0;
		}

		// 返回指定下标所对应的item的View对象
		// position:下标
		// convertView:可复用的缓存Item视图对象，前n+1个是为空
		// parent:ListView对象
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
    
    
			
			Log.e("TAG","测试："+"position:"+position+"convertView:"+convertView+"parent:"+parent);
			
			//判断如果没有复用
			if(convertView == null){
    
    //说明没有复用的视图对象，不断的在创建新的视图对象
				// 加载item的布局，得到View对象(得到XML页面的对象)
				convertView = View.inflate(MainActivity.this,
						R.layout.item_simple_adapter, null);
			}

			
			// 根据position设置对应的数据
			// 得到当前行的数据对象
			ShopInfo shopInfo = data.get(position);

			// 得到子View对象，得到XML页面上的子View对象
			ImageView imageView = (ImageView) convertView
					.findViewById(R.id.iv_item_icon);
			TextView name = (TextView) convertView.findViewById(R.id.tv_item_name);
			TextView contentTV = (TextView) convertView.findViewById(R.id.tv_item_content);
			// 设置数据
			imageView.setImageResource(shopInfo.getIcon());
			name.setText(shopInfo.getName());
			contentTV.setText(shopInfo.getContent());
			return convertView;
		}

	}
}

4、样式（Style）和主题（theme）

（1）实现上述效果：（Style）

a、创建新的安卓工程

b、修改style.xml

<style name="myStyle">
        <!--
		android:layout_width"="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:drawableLeft="@android:drawable/star_big_on"
        android:gravity="center_vertical"
        android:textSize="20sp"    
        -->
        <item name="android:layout_width">wrap_content</item>
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_marginLeft">10dp</item>
        <item name="android:drawableLeft">@android:drawable/star_big_on</item>
        <item name="android:gravity">center_vertical</item>
        <item name="android:textSize">20sp</item>
    </style>

c、修改activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <TextView
        style="@style/myStyle"
        android:text="SIM卡变更报警" />
    <TextView
        style="@style/myStyle"
        android:text="GPS追踪" />
    <TextView
        style="@style/myStyle"
        android:text="远程销毁数据" />
    <TextView
        style="@style/myStyle"
        android:text="远程锁屏" />
</LinearLayout>

效果

（3）主题（theme）

a、修改style.xml

<style name="myTheme" >
         <item name="android:textColor">#ff0000</item>
</style>

b、在AndroidManifest.xml当中引用对应的样式

运行样式

c、修改activity_main.xml当中一个单独的字体样式（最近优先原则）

d、引用没有标题样式（修改AndroidManifest.xml）

运行效果

e、引用全屏样式（修改AndroidManifest.xml）

f、对话框样式

二、应用练习

1、显示应用程序列表

（1）创建新的工程

（2）分析界面结构，编写布局

1）整体的布局文件：ListView：activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="所有应用" 
        android:gravity="center_horizontal"
        android:textSize="20sp"
        android:textColor="#ffffff"  
        android:background="#000000"
        android:padding="7dp"      
        />
    <ListView 
        	android:id="@+id/lv_main"
        	android:layout_width="match_parent"
        	android:layout_height="fill_parent"
        >
    </ListView>
</LinearLayout>

2）item的布局文件：RelativeLayout（相对布局）

创建新的布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <ImageView
        android:id="@+id/iv_item_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />
    <TextView
        android:id="@+id/tv_item_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/iv_item_icon"
        android:layout_centerInParent="true"
        android:text="应用名称"
        android:layout_marginLeft="10dp"
        android:textSize="20sp"
         />
</RelativeLayout>

（3）使用ListView+BaseAdapter显示所有应用信息的列表

1）得到所有应用信息数据对象的集合List<AppInfo>：得到了手机已经安装好应用信息的集合

创建类AppInfos

/*
	 * 得到手机当中所有的应用信息的列表
	 * AppInfo 
	 * Drawable 
	 * icon 
	 * String 
	 * appName 
	 * String 
	 * packageName
	 */
	protected List<AppInfo> getAllAppInfos() {
    
    
		List<AppInfo> list = new ArrayList<AppInfo>();
		// 得到应用的packgeManager
		PackageManager packageManager = getPackageManager();
		// 创建一个主界面的intent
		Intent intent = new Intent();
		intent.setAction(Intent.ACTION_MAIN);
		intent.addCategory(Intent.CATEGORY_LAUNCHER);
		// 得到包含应用信息的列表
		List<ResolveInfo> ResolveInfo = packageManager.queryIntentActivities(intent, 0);
		// 遍历
		for (ResolveInfo ri : ResolveInfo) {
    
    
			// 得到包名
			String packageName = ri.activityInfo.packageName;
			// 得到图标
			Drawable icon = ri.loadIcon(packageManager);
			// 得到应用名称
			String appName = ri.loadLabel(packageManager).toString();
			// 封装应用信息对象
			AppInfo appInfo = new AppInfo(icon, appName, packageName);
			list.add(appInfo);
		}
		return list;
	}

2）创建AppInfo封装类

package com.itzheng.app03_listview;

import android.graphics.drawable.Drawable;

/*
 * 应用信息的封装类
 */
public class AppInfo {
    
    

	private Drawable icon;// 应用图标

	private String appName;// 应用名称

	private String packageName;// 包名

	public AppInfo() {
    
    
		super();
		// TODO Auto-generated constructor stub
	}

	public AppInfo(Drawable icon, String appName, String packageName) {
    
    
		super();
		this.icon = icon;
		this.appName = appName;
		this.packageName = packageName;
	}

	public Drawable getIcon() {
    
    
		return icon;
	}

	public void setIcon(Drawable icon) {
    
    
		this.icon = icon;
	}
	public String getAppName() {
    
    
		return appName;
	}
	public void setAppName(String appName) {
    
    
		this.appName = appName;
	}
	public String getPackageName() {
    
    
		return packageName;
	}
	public void setPackageName(String packageName) {
    
    
		this.packageName = packageName;
	}
	@Override
	public String toString() {
    
    
		return "AppInfo [icon=" + icon + ", appName=" + appName
				+ ", packageName=" + packageName + "]";
	}
}

3）在MainActivity当中定义BaseAdapter的实现类：getView()，并加载页面实现显示所有应用信息

package com.itzheng.app03_listview;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
    
    
	private ListView lv_main;
	private List<AppInfo> data;
	private AppAdapter adapter;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// 初始化成员变量
		lv_main = (ListView) findViewById(R.id.lv_main);
		data = getAllAppInfos();
		adapter = new AppAdapter();
		// 显示列表
		lv_main.setAdapter(adapter);
	}
	class AppAdapter extends BaseAdapter {
    
    
		@Override
		public int getCount() {
    
    
			return data.size();
		}
		@Override
		public Object getItem(int position) {
    
    
			return data.get(position);
		}
		@Override
		public long getItemId(int position) {
    
    
			// TODO Auto-generated method stub
			return 0;
		}
		//返回带数据的当前行的Item视图对象
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
    
    
			//1、如果convertView是null，加载item的布局文件
			if(convertView == null){
    
    
				convertView = View.inflate(MainActivity.this, R.layout.item_main, null);
			}
			//2、得到当前行的数据对象
			AppInfo appInfo = data.get(position);
			//3、得到行所需要的更新的子View对象
			ImageView imageView = (ImageView) convertView.findViewById(R.id.iv_item_icon);
			TextView textView = (TextView) convertView.findViewById(R.id.tv_item_name);
			//4、给视图设置数据 
			imageView.setImageDrawable(appInfo.getIcon());
			textView.setText(appInfo.getAppName());
			//返回converView
			return convertView;
		}
	}
	/*
	 * 得到手机当中所有的应用信息的列表 AppInfo Drawable icon String appName String packageName
	 */
	protected List<AppInfo> getAllAppInfos() {
    
    
		List<AppInfo> list = new ArrayList<AppInfo>();
		// 得到应用的packgeManager:可以查询到以及安装好的应用信息
		PackageManager packageManager = getPackageManager();
		// 创建一个主界面的intent
		Intent intent = new Intent();
		intent.setAction(Intent.ACTION_MAIN);
		intent.addCategory(Intent.CATEGORY_LAUNCHER);
		// 得到包含应用信息的列表
		List<ResolveInfo> ResolveInfo = packageManager.queryIntentActivities(
				intent, 0);
		// 遍历
		for (ResolveInfo ri : ResolveInfo) {
    
    
			// 得到包名
			String packageName = ri.activityInfo.packageName;
			// 得到图标
			Drawable icon = ri.loadIcon(packageManager);
			// 得到应用名称
			String appName = ri.loadLabel(packageManager).toString();
			// 封装应用信息对象
			AppInfo appInfo = new AppInfo(icon, appName, packageName);
			list.add(appInfo);
		}
		return list;
	}
}

4）运行结果

（4）给ListView设置item的点击监听，在回调方法当中做响应：修改MainActivity当中的onCreate方法

// 给ListView设置item的点击监听，在回调方法当中做响应

		lv_main.setOnItemClickListener(new OnItemClickListener() {
    
    
			/*
			 * parnet:ListView view:当前行的item视图对象 position：当前行的下标
			 */
			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
    
    
				// 提示当前行的应用名称
				String appName = data.get(position).getAppName();
				// 提示
				Toast.makeText(MainActivity.this, appName, 0).show();
			}
		});

（5）给ListView设置item的长按监听，在回调方法当中做响应删除当前行，MainActivity实现OnItemLongClickListener

@Override
	public boolean onItemLongClick(AdapterView<?> parent, View view,
			int position, long id) {
    
    

		// 删除当前行

		// 删除当前行数据

		data.remove(position);

		// 更新列表

		// lv_main.setAdapter(adapter);//显示列表
		// 更新列表
		adapter.notifyDataSetChanged();// 通知更新列表

		return true;
	}

测试

2、手机卫士的主界面

（1）创建新的应用

（2）实现页面效果

a、界面布局

整体布局

<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gv_main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:numColumns="3"
    
     >

</GridView>

item布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:orientation="vertical"
    android:gravity="center"
    
     >

    <ImageView
        android:id="@+id/iv_item_icon"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/tv_item_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="名称"
        android:textSize="16sp" />

</LinearLayout>

b、使用GridView+BaseApdater显示界面

修改MainActivity类

package com.itzheng.app03_gridview;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.GridView;
public class MainActivity extends Activity {
    
    
	private GridView gv_main;
	private MainAdapter adapter;
	String[] names = new String[] {
    
     "手机防盗", "通讯卫士", "软件管理", "流量管理", "进程管理",
			"手机杀毒", "缓存管理", "高级工具", "设置中心" };
	int[] icons = new int[] {
    
     R.drawable.widget01, R.drawable.widget02,
			R.drawable.widget03, R.drawable.widget04, R.drawable.widget05,
			R.drawable.widget06, R.drawable.widget07, R.drawable.widget08,
			R.drawable.widget09 };
	@Override
	protected void onCreate(Bundle savedInstanceState) {
    
    
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		gv_main = (GridView) findViewById(R.id.gv_main);
		adapter = new MainAdapter(this,names,icons);
		gv_main.setAdapter(adapter);
	}
}

创建类MainAdapter

package com.itzheng.app03_gridview;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class MainAdapter extends BaseAdapter {
    
    
	private String[] names;
	private int[] icons;
	private Context context;
	public MainAdapter(Context context, String[] names, int[] icons) {
    
    
		super();
		this.names = names;
		this.icons = icons;
		this.context = context;
	}
	@Override
	public int getCount() {
    
    
		return names.length;
	}
	@Override
	public Object getItem(int position) {
    
    
		return names[position];
	}
	@Override
	public long getItemId(int position) {
    
    
		// TODO Auto-generated method stub
		return 0;
	}
	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
    
    
		// 判断当前页面上的元件是否为空
		if (convertView == null) {
    
    
			convertView = View.inflate(context, R.layout.item_main, null);
		}
		// 获取图片元件
		ImageView imageView = (ImageView) convertView
				.findViewById(R.id.iv_item_icon);
		// 获取文字元件
		TextView textView = (TextView) convertView
				.findViewById(R.id.tv_item_name);
		// 上述传入的图片依次放入到元件当中
		imageView.setImageResource(icons[position]);
		// 将上述文字信息放入到元件当中
		textView.setText(names[position]);
		return convertView;
	}
}

导入所需图片

c、给GridView设置Item的点击监听，并做响应

		// 给gridView 的Item设置点击监听
		gv_main.setOnItemClickListener(new OnItemClickListener() {
    
    
			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
    
    
				// 得到当前点击item的名称
				String name = names[position];
				// 提示
				Toast.makeText(MainActivity.this, name, 1).show();
			}
		});