Android 切换横竖屏

        <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>

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");

    }
}