隐式Intent

隐式Intent不明确指出我们想要启动哪个活动，而是指定了一系列的action、data或category等信息，然后交由系统去分析这个Intent,并帮我们找出合适的活动去启动

<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.example.intenttest.MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Button" />

</RelativeLayout>

package com.example.intenttest;

import com.example.menutest.R;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

	Button button=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		button=(Button) findViewById(R.id.button1);
		button.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				Intent intent=new Intent("com.example.intenttest.ACTION_START");
				intent.addCategory("com.example.intenttest.MY_CATEGORY");
				startActivity(intent);
			}
		});
	}

}

<?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" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="This is the Second Activity!"
        android:textSize="20dp" />

</LinearLayout>

package com.example.intenttest;

import com.example.menutest.R;

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity{

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

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

    <uses-sdk
        android:minSdkVersion="15"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.intenttest.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.intenttest.SecondActivity">
            <intent-filter>
                <action android:name="com.example.intenttest.ACTION_START" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="com.example.intenttest.MY_CATEGORY"/>
            </intent-filter>
        </activity>
    </application>
</manifest>