Question

我有一个使用意图的许多活动的应用程序。我有一个用于保存值的sharedPreferences方法。

我有一个欢迎屏幕，我设置在应用程序启动时显示（调用onCreate）。在同一个活动中，我删除了sharePreferences方法，所以当我重新打开应用程序时，欢迎屏幕将再次启动。

问题是，当我更改为另一个活动并再次返回主活动并按退出按钮时。当我再次启动应用程序时，它不会显示欢迎屏幕。我认为，主要活动仍然在运行，因此，onPause（），onStop（）和onDestroy（）永远不会被调用。当我保持相同的活动（主）并按退出时，它将调用onDestroy（）（包含擦除sharedPreferences方法）。

我没有设置finish（）方法。如果我设置了这个，那么每个移动的活动都会在Main活动中调用onDestroy，因此欢迎屏幕将在每次移动到该活动时启动。

我的mainactivity.java

 package com.bani.latihan;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RelativeLayout;

public class Main extends AppCompatActivity {


RelativeLayout PopupScreen, layoutAsli;

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
}

@Override
public void onDestroy(){
    super.onDestroy();


        SharedPreferences settings =     getSharedPreferences("PreferencesWelcome", Context.MODE_PRIVATE);
        settings.edit().remove("ditekan").apply();




}



@Override
public void onCreate(Bundle savedInstanceState) {
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
    super.onCreate(savedInstanceState);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setLogo(R.mipmap.ic_launcher);
    getSupportActionBar().setDisplayUseLogoEnabled(true);
    setContentView(R.layout.main);

    Button btn1 =(Button)findViewById(R.id.button1);
    final Button btn2 =(Button)findViewById(R.id.button2);
    PopupScreen = (RelativeLayout)findViewById(R.id.PopupScreen);
    layoutAsli = (RelativeLayout)findViewById(R.id.layoutAsli);

    btn1.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            Intent intent2 = new Intent(Main.this, Intent2.class);
            startActivity(intent2);


        }
    });

    btn2.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // TODO Auto-generated method stub
            moveTaskToBack(true);

            finish();



        }
    });




    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Isi dewek cuk!", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    EditText tvText = (EditText) findViewById(R.id.editText1);

    SharedPreferences prefs = getSharedPreferences("Preferences", Context.MODE_PRIVATE);
    if (prefs.contains("text")){
        tvText .setText(prefs.getString("text", ""));
    }
     SharedPreferences prefs2 = getSharedPreferences("PreferencesWelcome", Context.MODE_PRIVATE);
    if (prefs2.contains("ditekan")){
        PopupScreen.setVisibility(View.INVISIBLE);
        layoutAsli.setVisibility(View.VISIBLE);
    }


}
public void dismisWelcomeMessageBox(View view) {
    PopupScreen.setVisibility(View.INVISIBLE);
    layoutAsli.setVisibility(View.VISIBLE);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onPause() {
    super.onPause();
    EditText tvText = (EditText) findViewById(R.id.editText1);
    Button btWelcome = (Button) findViewById(R.id.button_welcome);
    SharedPreferences.Editor prefEditor = getSharedPreferences("Preferences", Context.MODE_PRIVATE).edit();
    SharedPreferences.Editor prefEditor2 = getSharedPreferences("PreferencesWelcome", Context.MODE_PRIVATE).edit();
    prefEditor.putString("text", tvText.getText().toString());
    prefEditor2.putBoolean("ditekan", btWelcome.isPressed());
    prefEditor.apply();
    prefEditor2.apply();
}



}

我的另一个活动代码：

    package com.bani.latihan;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.ImageView;

/**
  * Created by Bani Burhanuddin on 21/02/2016.
  */
public class Intent2 extends AppCompatActivity {

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

}




@Override
protected void onCreate(Bundle savedInstanceState) {
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
    super.onCreate(savedInstanceState);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setLogo(R.mipmap.ic_launcher);
    getSupportActionBar().setDisplayUseLogoEnabled(true);
    setContentView(R.layout.intent);

    Button btnnext = (Button) findViewById(R.id.button5);
    Button btnhome = (Button) findViewById(R.id.button6);
    Button btnback = (Button) findViewById(R.id.button7);

    btnnext.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent(Intent2.this, Intent3.class));
            finish();

        }
    });

    btnhome.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent(Intent2.this, Main.class));
            finish();

        }
    });

    btnback.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent(Intent2.this, Main.class));
            finish();

        }
    });

    CompoundButton toggle = (CompoundButton) findViewById(R.id.switch1);
    final ImageView imageView2 = (ImageView) findViewById(R.id.imageView2);
    imageView2.setVisibility(View.GONE);
    toggle.setOnCheckedChangeListener(new     CompoundButton.OnCheckedChangeListener() {
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {

                imageView2.setVisibility(View.VISIBLE);
            } else {

                imageView2.setVisibility(View.GONE);
            }
        }
    });


    SharedPreferences prefs = getSharedPreferences("Preferences2", Context.MODE_PRIVATE);
    if (prefs.contains("text2")) {
        toggle.setChecked(prefs.getBoolean("text2", true));
    }


}

@Override
public void onPause() {
    super.onPause();

    CompoundButton toggle = (CompoundButton) findViewById(R.id.switch1);
    if (toggle.isChecked()) {
        SharedPreferences.Editor editor = getSharedPreferences("Preferences2", MODE_PRIVATE).edit();
        editor.putBoolean("text2", true);
        editor.apply();
    } else {
        SharedPreferences.Editor editor = getSharedPreferences("Preferences2", MODE_PRIVATE).edit();
        editor.putBoolean("text2", false);
        editor.apply();
    }


}



}

我的清单

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <!-- Splash screen -->

    <activity
        android:name="com.bani.latihan.splashscreen"
        android:label="@string/app_name"
        android:screenOrientation="sensor"
        android:configChanges="keyboardHidden|orientation|screenSize"
        android:noHistory="true">


        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>


    <!-- Main activity -->

    <activity
        android:name="com.bani.latihan.Main"
        android:screenOrientation="sensor"
        android:label="@string/app_name"
        android:configChanges="keyboardHidden|orientation|screenSize">

    </activity>

    <!-- Intent2 activity -->

    <activity
        android:name=".Intent2"
        android:screenOrientation="sensor"
        android:noHistory="true"
        android:configChanges="keyboardHidden|orientation|screenSize">
    </activity>

    <!-- Intent3 activity -->

    <activity
        android:name=".Intent3"
        android:screenOrientation="sensor"
        android:configChanges="keyboardHidden|orientation|screenSize">
    </activity>

    <!-- Intent4 activity -->

    <activity
        android:name=".Intent4"
        android:screenOrientation="sensor"
        android:configChanges="keyboardHidden|orientation|screenSize">
    </activity>

</application>

</manifest>

我的主要布局

<RelativeLayout
    android:id="@+id/PopupScreen"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#123456"
    android:orientation="vertical"
    android:layout_margin="16dp"
    android:padding="16dp"
    android:visibility="visible">

    <TextView
        android:id="@+id/welcome_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginTop="16dp"
        android:text="@string/welcome"
        android:textColor="#ddd333"
        android:textSize="28sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/welcome_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/welcome_title"
        android:text="@string/welcome_message"
        android:textColor="#0dff00"
        android:textSize="18sp" />

    <Button
        android:layout_width="wrap_content"
        android:id="@+id/button_welcome"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_gravity="bottom"
        android:background="#3b978d"
        android:onClick="dismisWelcomeMessageBox"
        android:paddingLeft="30dp"
        android:paddingRight="30dp"
        android:text="@string/ok"
        android:textColor="#fff" />
</RelativeLayout>



<RelativeLayout
    android:id="@+id/layoutAsli"
    android:visibility="invisible"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    android:id="@+id/hello_world"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText1"
        android:layout_below="@+id/hello_world"/>

<FrameLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/imageView"

        android:src="@drawable/imageview"
        android:layout_gravity="center" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Next"
        android:id="@+id/button1"
        android:layout_marginTop="111dp"
        android:layout_centerHorizontal="true"
        android:layout_gravity="left|bottom" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Exit"
        android:id="@+id/button2"
        android:layout_below="@+id/button1"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="59dp"
        android:layout_gravity="right|bottom" />


</FrameLayout>


</RelativeLayout>


</RelativeLayout>

Answer 1

我遇到了你的问题。目前你正在使用MoveTaskToBack。它不会破坏活动，它只是在你完成之后回到活动堆栈中活动。所以它没有调用其他回调方法。它总是调用onDestroy 使用moveTasktoBack或完成。不要同时使用它们，这会让人感到困惑。

OnPause（）和onDestroy（）在其他活动打开时从未调用

1 个答案: