Android 切换横竖屏

一个项目一般会自己先定义项目是横屏还是竖屏但是也有可以横屏和竖屏之间切换的activty。

切换横竖屏的方法：

//判断当前屏幕方向
if(getRequestedOrientation() == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
    //切换竖屏
    MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}else{
    //切换横屏
    MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}　　

但是这样切换横竖屏会让activity重新加载。生命周期为：

　　onStop
　　onDestroy
　　onCreate
　　onStart
　　onResume

为了解决这样的问题在配置文件里加上

android:configChanges="orientation|keyboardHidden|screenSize"

就不会重新加载页面，只会进入到切换里面的生命周期中。

　　onConfigurationChanged

AndroidManifest.xml

        <activity android:name=".MainActivity"
            android:configChanges="orientation|keyboardHidden|screenSize"
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

MainActivity.java　

package com.kkrs.change;import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;public class MainActivity extends AppCompatActivity {    private Button change;    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        change = (Button)findViewById(R.id.change);
        Log.e("sys","onCreate");    }    @Override
    protected void onStart() {
        super.onStart();
        Log.e("sys","onStart");
        change.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("sys","被点击了");
                //判断当前屏幕方向
                if(getRequestedOrientation() == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
                    //切换竖屏
                    MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
                }else{
                    //切换横屏
                    MainActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
                }            }
        });
    }    //横竖屏切换
    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        Log.e("sys","onConfigurationChanged");    }    @Override
    protected void onStop() {
        super.onStop();
        Log.e("sys","onStop");    }    @Override
    protected void onResume() {
        super.onResume();
        Log.e("sys","onResume");
    }    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.e("sys","onDestroy");    }
}