Android状态栏的显示与隐藏

简述：
View类提供了setSystemUiVisibility方法传入的实参分析：

1. View.SYSTEM_UI_FLAG_VISIBLE：显示状态栏，
2. View.INVISIBLE：隐藏状态栏，
3. View.SYSTEM_UI_FLAG_FULLSCREEN：Activity全屏显示，且状态栏被隐藏覆盖掉。
4. View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN：全屏显示，但状态栏不会被隐藏覆盖，状态栏依然可见，顶端布局部分会被状态遮挡。
5. View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION：效果同View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
6. View.SYSTEM_UI_LAYOUT_FLAGS：效果同View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
7. View.SYSTEM_UI_FLAG_HIDE_NAVIGATION：隐藏虚拟按键(导航栏)。有些手机会用虚拟按键来代替物理按键。

8. View.SYSTEM_UI_FLAG_LOW_PROFILE：状态栏显示处于低能显示状态(low profile模式)，状态栏上一些图标显示会被隐藏。

    public class ColumnAtivity extends Activity implements View.OnClickListener {  @Override  protected void onCreate(@Nullable Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_column);    assignViews();    setOnClicks();}private LinearLayout mMain;private TextView mTextView;private Button mButton1;private Button mButton2;private Button mButton3;private Button mButton4;private Button mButton5;private Button mButton6;private Button mButton7;private void assignViews() {    mMain = (LinearLayout) findViewById(R.id.main);    mTextView = (TextView) findViewById(R.id.textView);    mButton1 = (Button) findViewById(R.id.button1);    mButton2 = (Button) findViewById(R.id.button2);    mButton3 = (Button) findViewById(R.id.button3);    mButton4 = (Button) findViewById(R.id.button4);    mButton5 = (Button) findViewById(R.id.button5);    mButton6 = (Button) findViewById(R.id.button6);    mButton7 = (Button) findViewById(R.id.button7);}private void setOnClicks() {    mButton1.setOnClickListener(this);    mButton2.setOnClickListener(this);    mButton3.setOnClickListener(this);    mButton4.setOnClickListener(this);    mButton5.setOnClickListener(this);    mButton6.setOnClickListener(this);    mButton7.setOnClickListener(this);}@Overridepublic void onClick(View v) {    switch (v.getId()) {        case R.id.button1:            //Activity全屏显示，且状态栏被隐藏覆盖掉            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN);            mTextView.setText("Activity全屏显示，且状态栏被隐藏覆盖掉\nView.SYSTEM_UI_FLAG_FULLSCREEN");            break;        case R.id.button2:            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE);            mTextView.setText("恢复到有状态的正常情况\nView.SYSTEM_UI_FLAG_VISIBLE");            break;        case R.id.button3:            mMain.setSystemUiVisibility(View.INVISIBLE);            mTextView.setText("//隐藏状态栏，同时Activity会伸展全屏显示\nView.INVISIBLE");            break;        case R.id.button4:            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);            mTextView.setText("Activity全屏显示，但状态栏不会被隐藏覆盖，状态栏依然可见，Activity顶端布局部分会被状态遮挡\nView"+                    ".SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN \n View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION");            break;        case R.id.button5:            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);            mTextView.setText("Activity全屏显示，状态栏透明\nView.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION");            break;        case R.id.button6:            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);            mTextView.setText("隐藏虚拟按键\nView.SYSTEM_UI_FLAG_HIDE_NAVIGATION");            break;        case R.id.button7:            mMain.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE);            mTextView.setText("状态栏低能显示，有一些会被隐藏\nView.SYSTEM_UI_FLAG_LOW_PROFILE");            break;        default:            break;    }}