通過Java程序碼, 運行時設置屏幕方向 - setRequestedOrientation()

上文"通過XML設置屏幕方向(android:screenOrientation)"中, 在AndroidManifest.xml文件設定屏幕方向. 這種方法有一個缺點:不能在程序運行時改變屏幕方向. 這篇文章用另一種方法 - 使用setRequestedOrientation()方法, 在程序運行時設置屏幕方向.



main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   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"
   />
<Button
   android:id="@+id/setrequestedorientation"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="Set Requested Orientation"
   />
</LinearLayout>

SetRequestedOrientationActivity.java 負責選擇屏幕方向.

package com.AndroidRequestedOrientation;

import android.app.ListActivity;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class SetRequestedOrientationActivity extends ListActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  
  setListAdapter(new ArrayAdapter<String>(this,
    android.R.layout.simple_list_item_1, OrientationString));
  getListView().setTextFilterEnabled(true);
 }

 static final String[] OrientationString = new String[] {
  "SCREEN_ORIENTATION_UNSPECIFIED",
  "SCREEN_ORIENTATION_LANDSCAPE",
  "SCREEN_ORIENTATION_PORTRAIT",
  "SCREEN_ORIENTATION_USER",
  "SCREEN_ORIENTATION_BEHIND",
  "SCREEN_ORIENTATION_SENSOR",
  "SCREEN_ORIENTATION_NOSENSOR"
 };
 
 static final int[] OrientationSetting = new int[] {
  ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED,
  ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE,
  ActivityInfo.SCREEN_ORIENTATION_PORTRAIT,
  ActivityInfo.SCREEN_ORIENTATION_USER,
  ActivityInfo.SCREEN_ORIENTATION_BEHIND,
  ActivityInfo.SCREEN_ORIENTATION_SENSOR,
  ActivityInfo.SCREEN_ORIENTATION_NOSENSOR
 };

 @Override
 protected void onListItemClick(ListView l, View v, int position, long id) {
  // TODO Auto-generated method stub
  super.onListItemClick(l, v, position, id);
  
  Intent intent = new Intent();
     Bundle bundle = new Bundle();
  
     bundle.putInt("setting", OrientationSetting[position]);
     intent.putExtras(bundle);
     setResult(RESULT_OK, intent);
     finish();
 }
 
}

主代碼 - AndroidRequestedOrientation.java
在onActivityResult()方法, 從SetRequestedOrientationActivity返回值, 使用setRequestedOrientation()方法, 設置屏幕方向.

package com.AndroidRequestedOrientation;

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

public class AndroidRequestedOrientation extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       Button buttonSetRequestedOrientation = (Button)findViewById(R.id.setrequestedorientation);
       buttonSetRequestedOrientation.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    Intent intent = new Intent();
    intent.setClass(AndroidRequestedOrientation.this,
      SetRequestedOrientationActivity.class);
           
    startActivityForResult(intent, 0);
   }});
   }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  // TODO Auto-generated method stub
  super.onActivityResult(requestCode, resultCode, data);
  
  if (requestCode==0)
  {
   if(resultCode == RESULT_OK){
    int OrientationSetting = data.getIntExtra("setting",
      ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
    setRequestedOrientation(OrientationSetting);
   }
  }
 }
}

記得在AndroidManifest.xml文件加入SetRequestedOrientationActivity活動.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.AndroidRequestedOrientation"
     android:versionCode="1"
     android:versionName="1.0">
   <application android:icon="@drawable/icon" android:label="@string/app_name">
       <activity android:name=".AndroidRequestedOrientation"
                 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=".SetRequestedOrientationActivity"></activity>
   </application>
   <uses-sdk android:minSdkVersion="4" />

</manifest>