android锁屏显示

首先简单说一下实现的思路，在MainActivity中启动一个服务，服务中注册锁屏广播监听，监听到锁屏状态改变启动LockScreenActivity作为锁屏页面，实现如下：
首先在MainActivity的布局中写一个SwitchCompat用于开关锁屏。 

MainActivity的逻辑如下所示，这里没有做状态保持，实际开发可以简单的通过SP实现。 

public class MainActivity extends AppCompatActivity {

    private SwitchCompat mOpenLockScreenSWC;

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

    private void initView() {
        mOpenLockScreenSWC = (SwitchCompat) findViewById(R.id.swc_lockscreen_open);
        mOpenLockScreenSWC.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked) {
                    //开启锁屏服务
                    startLockScreen();
                } else {
                    //关闭锁屏服务
                    stopLockScreen();
                }
            }
        });
    }

    /**
     * 开启锁屏服务
     */
    public void startLockScreen(){
        Intent intent = new Intent(MainActivity.this,LockScreenService.class);
        this.startService(intent);
    }

    /**
     * 关闭锁屏服务
     */
    public void stopLockScreen(){
        Intent intent = new Intent(MainActivity.this,LockScreenService.class);
        this.stopService(intent);
    }

}

 下面是服务的代码。

public class LockScreenService extends Service {
    private final String TAG = "LockScreenService";

    private LockScreenBroadcastReceiver mReceiver = null;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.i(TAG,"onCreate => ");
        mReceiver = new LockScreenBroadcastReceiver();

        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_USER_PRESENT);
        registerReceiver(mReceiver,filter);

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        Log.i(TAG,"onStartCommand => 启动了服务");
        return super.onStartCommand(intent, flags, startId);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i(TAG,"onDestroy => 销毁了服务");
        if(mReceiver != null){
            unregisterReceiver(mReceiver);
        }
    }
}

 广播接收的代码。

public class LockScreenBroadcastReceiver extends BroadcastReceiver {
    private final String TAG = "LockScreenBR";

    @Override
    public void onReceive(final Context context, Intent intent) {

        if (intent != null) {
            String action = intent.getAction();
            Log.i(TAG, "LockScreenBroadcastReceiver => receiver => [action : " + action + "]");

            if (action != null && action.equals(Intent.ACTION_SCREEN_ON)) {
                //开启
                try {
                    Intent startIntent = new Intent(context, LockScreenActivity.class);
                    startIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                            | Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS
                    );
                    context.startActivity(startIntent);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

        }
    }
}

 锁屏页面的布局简单的写一个。

锁屏页面要做一些特殊的处理，比如设置锁屏显示，设置隐藏虚拟按键等，（如果需要显示时间日期就监听系统时间显示，当然还有手势解锁，滑动解锁）我这里只做简单展示。 

public class LockScreenActivity extends AppCompatActivity {

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

        //设置当前Activity的锁屏显示
        KeyguardManager km = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
        KeyguardManager.KeyguardLock keyguardLock = km.newKeyguardLock("1");
        keyguardLock.disableKeyguard();
        this.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);

        setContentView(R.layout.activity_lock_screen);

        //隐藏虚拟按键
        hideBottomButton();
    }

    /**
     * 隐藏虚拟按键
     */
    private void hideBottomButton() {
        try{
            //隐藏虚拟按键
            if (Build.VERSION.SDK_INT > 11 && Build.VERSION.SDK_INT < 19) {
                View v = getWindow().getDecorView();
                v.setSystemUiVisibility(View.GONE);
            } else if (Build.VERSION.SDK_INT >= 19) {
                View decorView = getWindow().getDecorView();
                int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                        | View.SYSTEM_UI_FLAG_FULLSCREEN;
                decorView.setSystemUiVisibility(uiOptions);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

AndroidManifest.xml如下。

 最后安装之后需要去设置页面给当前应用锁屏显示的权限，如下图所示。

以上的代码只是一个实现思路，如果要开发商用还有很多地方需要完善。