上官网学android之八（Interacting with Other Apps）

官网地址

http://developer.android.com/training/basics/intents/index.html

 

转眼间到了，Getting Started的最后一小节了，这次要学的是如何和其它的APP进行交互

一、发送动作到其它APP(原文是Sending the user to Another App)

 

1.1 建立一个Intent

在Android 中Intent是一种运行时绑定机制它可以再运行时连接两个不同的组件。

下面代码是官网上各种不同的Intent小例子

 

//拨电话
Uri number = Uri.parse("tel:[phone]");
Intent callIntent = new Intent(Intent.ACTION_DIAL, number);
//地图
Uri location = Uri.parse("geo:0,0?q=1600+Amphitheatre+Parkway,+Mountain+View,+California");
Intent mapIntent = new Intent(Intent.ACTION_VIEW, location);
//网页
Uri webpage = Uri.parse("http://www.android.com");
Intent webIntent = new Intent(Intent.ACTION_VIEW, webpage);
//email
Intent emailIntent = new Intent(Intent.ACTION_SEND);
emailIntent.setType(HTTP.PLAIN_TEXT_TYPE);
emailIntent.putExtra(Intent.EXTRA_EMAIL, new String[] {"[e-mail]"}); // recipients
emailIntent.putExtra(Intent.EXTRA_SUBJECT, "Email subject");
emailIntent.putExtra(Intent.EXTRA_TEXT, "Email message text");
emailIntent.putExtra(Intent.EXTRA_STREAM, Uri.parse("content://path/to/email/attachment"));
//日历
Intent calendarIntent = new Intent(Intent.ACTION_INSERT, Events.CONTENT_URI);
Calendar beginTime = Calendar.getInstance().set(2012, 0, 19, 7, 30);
Calendar endTime = Calendar.getInstance().set(2012, 0, 19, 10, 30);
calendarIntent.putExtra(CalendarContract.EXTRA_EVENT_BEGIN_TIME, beginTime.getTimeInMillis());
calendarIntent.putExtra(CalendarContract.EXTRA_EVENT_END_TIME, endTime.getTimeInMillis());
calendarIntent.putExtra(Events.TITLE, "Ninja class");
calendarIntent.putExtra(Events.EVENT_LOCATION, "Secret dojo");

 

1.2 验证是否有一个Activity去接收Intent

 

 

PackageManager packageManager = getPackageManager();
List<ResolveInfo> activities = packageManager.queryIntentActivities(intent, 0);
boolean isIntentSafe = activities.size() > 0;
//如果isIntentSafe ==true 说明至少有一个Activity接收

 

1.3 启动一个有Intent的Activity

很简单调用startActivity(intent)方法，里面接收一个Intent实例即可，下面是实例

Uri location = Uri.parse("geo:0,0?q=1600+Amphitheatre+Parkway,+Mountain+View,+California");
Intent mapIntent = new Intent(Intent.ACTION_VIEW, location);

// Verify it resolves
PackageManager packageManager = getPackageManager();
List<ResolveInfo> activities = packageManager.queryIntentActivities(mapIntent, 0);
boolean isIntentSafe = activities.size() > 0;

// Start an activity if it's safe
if (isIntentSafe) {
    startActivity(mapIntent);
}

 

1.4 显示一个APP选择框

如果有N个Activity可以接收你的Intent，这时候你得让用户选择一个他最喜欢的。

Intent intent = new Intent(Intent.ACTION_SEND);

// Always use string resources for UI text.
// This says something like "Share this photo with"
String title = getResources().getString(R.string.chooser_title);
// Create intent to show chooser
Intent chooser = Intent.createChooser(intent, title);

// Verify the intent will resolve to at least one activity
if (intent.resolveActivity(getPackageManager()) != null) {
    startActivity(chooser);
}

 

二、从一个Activity得到一个结果

有时候我们启动一个Activity是喜欢得到它的结果，比如说选择联系人：）

下面是一个选择电话联系人的例子

public class MainActivity extends Activity {

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

		getIntentResultTest();
	}

	static final int PICK_CONTACT_REQUEST = 1; // The request code

	private void getIntentResultTest() {
		Intent pickContactIntent = new Intent(Intent.ACTION_PICK,
				Uri.parse("content://contacts"));
		pickContactIntent.setType(Phone.CONTENT_TYPE); // Show user only
														// contacts w/ phone
														// numbers
		startActivityForResult(pickContactIntent, PICK_CONTACT_REQUEST);
	}

	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		if (requestCode == PICK_CONTACT_REQUEST) {
			if (resultCode == RESULT_OK) {
				Uri contactUri = data.getData();
				String[] projection = { Phone.NUMBER };

				Cursor cursor = getContentResolver().query(contactUri,
						projection, null, null, null);
				cursor.moveToFirst();

				int column = cursor.getColumnIndex(Phone.NUMBER);
				String number = cursor.getString(column);

				Log.i("intent_result_test", "number is :" + number);
			}
		}
	}
......

 

三、允许其它的APP启动你的Activity

前面都是调用别的Activity,现在反过来，让别人调用你的

3.1 添加一个Activity Filter

你需要定义下你能处理什么样的Intent，比如下面定义的Activity可以处理ACTION_SEND的Intent,data type 是text 或者 图像（image）

<activity android:name="ShareActivity">
    <intent-filter>
        <action android:name="android.intent.action.SEND"/>
        <category android:name="android.intent.category.DEFAULT"/>
        <data android:mimeType="text/plain"/>
        <data android:mimeType="image/*"/>
    </intent-filter>
</activity>

 如果你的Activity能处理两种Action呢比如，ACTION_SEND  和 ACTION_SENDTO，你需要定义两个intent filters.

<activity android:name="ShareActivity">
    <!-- filter for sending text; accepts SENDTO action with sms URI schemes -->
    <intent-filter>
        <action android:name="android.intent.action.SENDTO"/>
        <category android:name="android.intent.category.DEFAULT"/>
        <data android:scheme="sms" />
        <data android:scheme="smsto" />
    </intent-filter>
    <!-- filter for sending text or images; accepts SEND action and text or image data -->
    <intent-filter>
        <action android:name="android.intent.action.SEND"/>
        <category android:name="android.intent.category.DEFAULT"/>
        <data android:mimeType="image/*"/>
        <data android:mimeType="text/plain"/>
    </intent-filter>
</activity>

 

3.2 在Activity中处理Intent

上面已经告诉系统我们的Activity可以处理那些Intent，接下来我们要真正处理这些Intent了。

我们可以在Activity任何生命周期阶段，但是通常在onCreate()或者onStart()方法。

 

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    // Get the intent that started this activity
    Intent intent = getIntent();
    Uri data = intent.getData();

    // Figure out what to do based on the intent type
    if (intent.getType().indexOf("image/") != -1) {
        // Handle intents with image data ...
    } else if (intent.getType().equals("text/plain")) {
        // Handle intents with text ...
    }
}

 

3.3  返回一个结果

还记得之前有选择联系人的情况，所以有的时候你可能需要返回一个结果。

返回一个结果很简单， setResult()方法即可完成任务

Intent result = new Intent("com.example.RESULT_ACTION", Uri.parse("content://result_uri");
setResult(Activity.RESULT_OK, result);
finish()

 通常总会返回一个Result code在一个result中，比如RESULT_OK,RESULT_CANELED。

也有的情况只需要一个简单的整形值而已

setResult(RESULT_COLOR_RED);
finish();