安卓UI入门学习（android studio）（二）

三、自定义控件
①title.xml中的代码

<?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:background="@drawable/bg_bottombar_center_normal">
    <Button
        android:id="@+id/title_bcak"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_margin="5dp"
        android:background="@drawable/bg_chat_dis_normal"
        android:text="Back"
        android:textColor="#fff"
        />
    <TextView
        android:id="@+id/title_text"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1"
        android:gravity="center"
        android:text="Title Text"
        android:textColor="#fff"
        android:textSize="24sp"
        />
    <Button
        android:id="@+id/title_edit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_margin="5dp"
        android:background="@drawable/bg_chat_active"
        android:text="Edit"
        android:textColor="#fff"
        />


</LinearLayout>

②main_layout.xml中的代码

<?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">
   <com.example.ewewwfef.anewtest.TitleLayout
       android:layout_width="match_parent"
       android:layout_height="wrap_content">

   </com.example.ewewwfef.anewtest.TitleLayout>
</LinearLayout>

③TitleLayout.java中的代码

package com.example.ewewwfef.anewtest;

import android.app.Activity;
import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;

/**
 * Created by ewewwfef on 2018/3/18.
 */

public class TitleLayout extends LinearLayout {
    public  TitleLayout(Context context, AttributeSet attrs)
    {
        super(context,attrs);
        LayoutInflater.from(context).inflate(R.layout.title,this);
        Button titleBack=(Button)findViewById(R.id.title_bcak);
        Button titleEdit=(Button)findViewById(R.id.title_edit);
        titleBack.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                ((Activity)getContext()).finish();
            }
        });
        titleEdit.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getContext(),"You clicked Edit button",Toast.LENGTH_SHORT).show();
            }
        });
    }
}

④主活动中的代码

package com.example.ewewwfef.anewtest;

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);
        ActionBar actionBar=getSupportActionBar();
        if(actionBar!=null)
            actionBar.hide();
    }
}

四、ListView
Main_layout中的代码

<ListView
    android:id="@+id/list_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</ListView>

主活动中的代码

public class MainActivity extends AppCompatActivity {


    private String[]data={"Apple","Banana","Orange","Watermelon",
            "Pear","Grape","Pineapple","Strawberry","cherry","Mango",
            "Apple","Banana","Orange","Watermelon", "Pear","Grape",
            "Pineapple","Strawberry","cherry","Mango"
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);
        ArrayAdapter<String>adapter=new ArrayAdapter<String>(
                MainActivity.this,android.R.layout.simple_list_item_1,data
        );
        ListView listView=(ListView)findViewById(R.id.list_view);
        listView.setAdapter(adapter);
    }

在主程序中，使用了ArrayAdapter作为适配器，来储存data中的数据。 最后需要调用setAdapter，将适配的数据传入

五、定制listview界面，以使其显得更丰富
①Fruit类中的代码

package com.example.ewewwfef.anewtest;

/**
 * Created by ewewwfef on 2018/3/18.
 */

public class Fruit {
    private  String name;
    private  int inmageId;
    public  Fruit(String name,int imageId)
    {
        this.name=name;
        this.inmageId=imageId;
    }
    public String getName()
    {
        return name;

    }
    public  int getInmageId()
    {
        return  inmageId;
    }
}

②fruit_item.xml中的代码

<?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">
    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="10dp"
        />
</LinearLayout>

③main_layout.xml中的代码

<?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">
    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="10dp"
        />
</LinearLayout>

④FruitAdapter.java中的代码

package com.example.ewewwfef.anewtest;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;

/**
 * Created by ewewwfef on 2018/3/18.
 */

public class FruitAdapter extends ArrayAdapter<Fruit> {
    private  int resourceId;

    public  FruitAdapter(Context context, int textViewResourceId,
                         List<Fruit> objects)
    {
        super(context,textViewResourceId,objects);
        resourceId=textViewResourceId;
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        Fruit fruit=getItem(position);
        View view= LayoutInflater.from(getContext()).inflate(resourceId,parent,
                false);
        ImageView fruitImage=(ImageView)view.findViewById(R.id.fruit_image);
        TextView fruitName=(TextView)view.findViewById(R.id.fruit_name);
        fruitImage.setImageResource(fruit.getInmageId());
        fruitName.setText(fruit.getName());
        return  view;
    }
}

⑤MainActivity.java中的代码

package com.example.ewewwfef.anewtest;

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private List<Fruit> fruitList=new ArrayList<>();
    @Override
    protected void  onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);
        initFruit();
        FruitAdapter adapter=new FruitAdapter(MainActivity.this,R.layout.fruit_item,
                fruitList);
        ListView listView=(ListView)findViewById(R.id.list_view);
        listView.setAdapter(adapter);
    }
    private  void  initFruit()
    {
        for(int i=0;i<2;i++)
        {
            Fruit apple=new Fruit("Apple",R.drawable.apple_img);
            fruitList.add(apple);
            Fruit banana=new Fruit("Bnanana",R.drawable.banana_img);
            fruitList.add(banana);
            Fruit orange=new Fruit("Orange",R.drawable.orange_img);
            fruitList.add(orange);
            Fruit watermelon=new Fruit("Watermelon",R.drawable.watermelon_img);
            fruitList.add(watermelon);
            Fruit pear=new Fruit("Pear",R.drawable.pear_img);
            fruitList.add(pear);
            Fruit grape=new Fruit("Grape",R.drawable.grape_img);
            fruitList.add(grape);
            Fruit pineapple=new Fruit("Pineapple",R.drawable.pineapple_img);
            fruitList.add(pineapple);
            Fruit strawberry=new Fruit("Strawberry",R.drawable.strawberry_img);
            fruitList.add(strawberry);
            Fruit cherry=new Fruit("Cherry",R.drawable.cherry_img);
            fruitList.add(cherry);
            Fruit mongo=new Fruit("Mongo",R.drawable.mongo_img);
            fruitList.add(mongo);
        }
    }
}

这个程序的实现总共有五个文件完成的，其中有两个.xml文件，三个.java文件实现的 其中最为简单的便是Fruit.java文件，在这个文件中定义了Fruit对象能够返回图片的地址以及水果的名称。 而FruitAdapter是一继承了个ArrayAadapter的类