當用戶點擊home鍵,在onPause()和的onStop()被調用。當他們點擊後退按鈕(退出應用程序)時,會調用onPause(),onStop(),最後調用onDestory()。最後,當他們按下電源按鈕時,onPause()和onStop()被調用。
他們都先onPause()被調用。覆蓋onPause()並使用intent返回到主要活動。您也可以清除一堆活動,以便它們不能點擊後退按鈕返回到一個。
MainActivity
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button goPrivate = (Button) findViewById(R.id.goPrivate);
goPrivate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this, Private.class));
}
});
}
}
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.vzw.www.myapplication.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="MAIN"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="GO TO PRIVATE"
android:id="@+id/goPrivate"/>
</RelativeLayout>
創建一個新的活動。我將其命名Private.java
Private.java
public class Private extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_private);
}
@Override
protected void onPause() {
super.onPause();
startActivity(new Intent(Private.this, MainActivity.class));
}
}
activity_private.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.vzw.www.myapplication.Private"
android:layout_gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="PRIVATE!"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
只需創建Android Studio中一個空白的項目和嘗試。有用! :)
如果我們點擊進入另一項活動並深入應用程序會發生什麼?
在Private類中創建一個布爾值。
boolean goSuperClicked = false;
更新私有類低於:
public class Private extends AppCompatActivity {
Button goSuper;
boolean goSuperClicked = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_private);
goSuper = (Button) findViewById(R.id.goSuper);
goSuper.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
goSuperClicked = true;
startActivity(new Intent(Private.this, SuperPrivate.class));
}
});
}
@Override
protected void onPause() {
super.onPause();
Log.d("onPause()", "onPause called");
if (!goSuperClicked) {
startActivity(new Intent(Private.this, MainActivity.class));
}
}
}
https://stackoverflow.com/questions/8317331/detecting-when-screen-is-locked – litelite
它這樣做是因爲您正在啓動主要活動,而不管屏幕關閉時發生了什麼。您沒有邏輯來區分剛剛使用該應用程序的用戶。 –