Android显式意图、隐式意图、意图过滤器(intent-filter)、意图间传值

浏览数：29 / 时间：2015年06月11日

intent主要包括隐式意图和显式意图。显式意图通常主要是启动本应用中的Activity之间的数据，而隐式意图则常见于启动系统中的某些特定的动作，比如打电话，发短信，或者是跨应用的Activity启动（如在QQ点击链接地址启动一个浏览器Activity）。

显式意图：调用Intent.setComponent()、Intent.setClass()、Intent.setClassName()方法明确指定了组件名的Intent为显式意图，显式意图明确指定了Intent应该传递给哪个组件。
隐式意图：没有明确指定组件名的Intent为隐式意图。 Android系统会根据隐式意图中设置的动作(action)、类别(category)、数据（URI和数据类型）找到最合适的组件来处理这个意图。

MainActivity.java

package cn.android.intent;

import java.util.Date;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.TextView;

public class NewActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.other);
		Intent intent = getIntent();
		//Log.i("NewActivity", intent.getData().getPath());
		String title = intent.getStringExtra("title");
		double since = intent.getDoubleExtra("since", 1995.5);
		TextView textView = (TextView) this.findViewById(R.id.textView);
		textView.setText("语言：" + title + "，发布时间：" + since + "。");
	}
	
	public void closeActivity(View v) {
		Intent intent = new Intent();
		intent.putExtra("result", new Date().toString());
		setResult(501, intent);
		this.finish();
	}
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
	    if (keyCode == KeyEvent.KEYCODE_BACK) {
	    	closeActivity(null);
	    }
	    return true;
	}
}

NewActivity.java

package cn.android.intent;

import java.util.Date;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.TextView;

public class NewActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.other);
		Intent intent = getIntent();
		//Log.i("NewActivity", intent.getData().getPath());
		String title = intent.getStringExtra("title");
		double since = intent.getDoubleExtra("since", 1995.5);
		TextView textView = (TextView) this.findViewById(R.id.textView);
		textView.setText("语言：" + title + "，发布时间：" + since + "。");
	}
	
	public void closeActivity(View v) {
		Intent intent = new Intent();
		intent.putExtra("result", new Date().toString());
		setResult(501, intent);
		this.finish();
	}
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
	    if (keyCode == KeyEvent.KEYCODE_BACK) {
	    	closeActivity(null);
	    }
	    return true;
	}
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello"
        android:id="@+id/textView" />
    <LinearLayout 
        android:layout_width="fill_parent"
    	android:layout_height="fill_parent"
    	android:orientation="horizontal"
    	android:gravity="center_horizontal"
    	android:layout_below="@id/textView">
	    <Button 
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:text="@string/button_display"
	        android:id="@+id/buttonDisplay"
	        android:onClick="openActivityDisplay" />
	    <Button 
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:text="@string/button_hidden"
			android:onClick="openActivityHidden" />    
    </LinearLayout>
</RelativeLayout>

other.xml

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
	<TableRow>
	    <TextView
	        android:layout_width="fill_parent"
	        android:layout_height="wrap_content"
	        android:text="@string/newActivity"
	        android:id="@+id/textView" />
	    <Button 
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:text="@string/button_close"
	        android:onClick="closeActivity" />
    </TableRow>
</TableLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.android.intent"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".MainActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".NewActivity" android:label="@string/newActivity">
            <intent-filter>
                <action android:name="cn.java.action.android" />
                <action android:name="cn.java.action.windowsphone" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="cn.java.category.intent" />
                <category android:name="cn.java.category.action" />
                <data android:scheme="intent" android:host="www.android.com" />
                <data android:mimeType="image/*" />
            </intent-filter>
        </activity>
    </application>

</manifest>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World, MainActivity!</string>
    <string name="newActivity">New Activity!</string>
    <string name="app_name">Android意图</string>
	<string name="button_display">打开显示意图</string>
	<string name="button_hidden">打开隐式意图</string>
	<string name="button_close">关闭窗口</string>
</resources>