Detailed core Android Application Intent

A, Intent outlines its properties

Intent basic applications:

1. Open a activity
2. Open a Service
3. Broadcast delivery

Intent object attributes:

For an Intent object, actually a group of information is bundled.

1. Component name (component name): Set the component name Intent objects may be initiated activity or other activity provided by other applications Component name, an activity can be uniquely determined by the class name and the package name specified component name.
   Available ** setComponent () ** method is provided, an object to be passed Component name.
   Creating a Component name the object to be passed two parameters: the application package name, class name (class name to be included in the full package name).

        Button button= (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //创建一个Intent对象
                Intent intent=new Intent();
                //创建一个CompnentName对象
                ComponentName componentName=new ComponentName("com.mingrisoft.demo2","com.mingrisoft.demo2.DetailActivity");
                //设置意图
                intent.setComponent(componentName);
                //启动另一个activity
                startActivity(intent);
            }
        });

2. Action and the Data
   Action attribute: used to specify the action to be performed.
   Data attribute: Specifies the specific data.
   Under normal circumstances, we are used together to express a specific meaning.
   For example: For example Action is what I want to drink ... and drink what is it? Data then you need to specify specific things, water? Tea? and many more.

Example: Using Intent to realize on the page to make calls and send SMS functions.

Results are as follows:

activity_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.mingrisoft.intent_action_data.MainActivity">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="公司：陈小猪和刘大狗" />

    <ImageButton
        android:id="@+id/bt2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/text"
        android:layout_marginTop="10dp"
        android:layout_marginRight="10dp"
        android:background="#0000"
        android:src="@drawable/e1"/>

    <ImageButton
        android:id="@+id/bt1"
        android:layout_below="@+id/text"
        android:layout_toRightOf="@+id/bt2"
        android:layout_marginTop="10dp"
        android:background="#0000"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/e2"/>


</RelativeLayout>

MainActivity.java file

package com.mingrisoft.intent_action_data;

import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ImageButton bt1= (ImageButton) findViewById(R.id.bt1);
        ImageButton bt2= (ImageButton) findViewById(R.id.bt2);
        bt1.setOnClickListener(l);
        bt2.setOnClickListener(l);
    }
    //由于两个按钮的事件监听器比较像，所以可以直接设置一个事件监听器对象。
    View.OnClickListener l=new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent=new Intent();
            ImageButton imageButton= (ImageButton) view;
            switch (imageButton.getId())
            {
                case R.id.bt1:
                    intent.setAction(intent.ACTION_DIAL);
                    intent.setData(Uri.parse("tel:0431849876"));
                    startActivity(intent);
                    break;

                case R.id.bt2:
                    intent.setAction(intent.ACTION_SENDTO);
                    intent.setData(Uri.parse("smsto:0431849876"));
                    intent.putExtra("sms_body","Welcome to ");
                    startActivity(intent);
                    break;

            }
        }
    };
}

manefests file

    <!-- 开启打电话的权限-->
    <uses-permission android:name="android.permission.CALL_PHONE"/>
    <uses-permission android:name="android.permission.SEND_SMS"/>

3. Category Action and
   both are often used together, they can be called by the system startup activity or other application components android system

Category is used to perform the operation described categories.
View property on their own API.

Example: Using Intent analog closed Google Map desktop.

activity_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.mingrisoft.goodle_intent.MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#0000"
        android:textSize="20sp"
        android:layout_marginLeft="160dp"
        android:layout_marginBottom="70dp"
        android:layout_alignParentBottom="true"
        android:text="关闭" />
</RelativeLayout>

MainActivity.java file

package com.mingrisoft.goodle_intent;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        Button bt= (Button) findViewById(R.id.button);
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                //作为初始Activity启动
                intent.setAction(intent.ACTION_MAIN);
                //返回桌面
                intent.addCategory(intent.CATEGORY_HOME);
                //启动Intent9
                startActivity(intent);
            }
        });
    }
}

4.Extras属性
putExtras()方法：用来把Bundle作为附加数据进行添加。
getExtras（）方法：获取保存的Bundle信息。

应用场景：
用于多个Activity进行数据交换时。

5.Flag属性：
①用来指示Android程序如何去启动另一个Activity，如让该Activity属于哪个Task。
Task:以栈的模式聚集在一起的Activity组件的结合。
②指示程序启动后如何处理，如：指示它是否为近期的Activity。
同样参考Android API找提供的常量来设置

                //让当前Activity不在历史栈中保留，用户一旦离开他，这个Activity自动关闭
                intent.setFlags(intent.FLAG_ACTIVITY_NO_HISTORY);

二、Intent种类

1.显式Intent
2.隐式Intent

显式Intent

创建Intent对象的语法格式：

Intent intent=new Intent (Context packageContext,Class<?>cls)
第一个参数一般为MainActivity.this,第二个参数为要启动的Activity的类，例如DeatailActivity.class。

隐式Intent

        Button button= (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //隐式Intent
                Intent intent=new Intent();
                //把数据显示给用户
                intent.setAction(intent.ACTION_VIEW);
                intent.setData(Uri.parse("http://www.mingribook.com"));
                startActivity(intent);

            }
        });

显式Intent和隐式Intent的区别。

显式Intent:

• 直接指定目标组件的名称
• 多用于在应用程序内传递信息

隐式Intent：

• 不会用组件名称定义要激活的目标组件
• 多用于在不同应用程序之间传递信息。因为开发人员不清楚其他应用程序的组件名称。

三、Intent过滤器

过滤器：一种根据某一个Intent的Action,Data以及Category等属性，对适合接受这个Intent的组件，进行匹配和筛选的机制。主要使用在使用隐式Intent启动activity时。

例子：

在ActivityA中调用startActivity（）打开另一个目标组件，但不直接指定要打开的组件，而是设置一个过滤器，能通过过滤器的组件即要打开的组件。

Set the filter
through <intent-filter disposed in Manifest.xml file marker.

<intent-filter>
	//指定组件能响应的动作
	<action...../>
	//指定以哪种方式执行Intent请求的动作
	<category...../>
	//想action提供要操作的数据
	<data...../>
</intent-filter>

Two commonly used filters:
1.
2

Example: Start another Acticity implicit predefined action comprises Intent in an Activity.

Effect:

activity_main.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.mingrisoft.lookbigger.MainActivity">

    <ImageView
        android:layout_centerHorizontal="true"
        android:id="@+id/image"
        android:layout_width="150dp"
        android:layout_height="200dp"
        android:src="@drawable/t3"/>

    <Button
        android:id="@+id/button"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="查看大图"
        android:layout_below="@+id/image"/>
</RelativeLayout>

MainActivity.java file

package com.mingrisoft.lookbigger;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button= (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.setAction(intent.ACTION_VIEW);
                startActivity(intent);
            }
        });
    }
}

activity_show.xml file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.mingrisoft.lookbigger.ShowActivity">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/t3"
        android:scaleType="fitXY"/>
</RelativeLayout>

ShowActivity.java file does not change