アプリケーションを閉じて、バックグラウンドで実行されないようにしたいです。
どうすればいいでしょうか? これは Android プラットフォームでは良い方法でしょうか?
「戻る」ボタンに頼ると、アプリは閉じますが、バックグラウンドに残ります。バックグラウンドのアプリを強制終了するための「TaskKiller」というアプリケーションもあります。
ベストアンサー1
Androidには、ドキュメントに従ってアプリケーションを安全に終了するメカニズムがあります。終了する最後のアクティビティ（通常はアプリケーションの開始時に最初に表示されたメインアクティビティ）のonDestroy()メソッドに数行追加するだけです。System.runFinalizersOnExit(true)アプリケーション終了時にすべてのオブジェクトがファイナライズされ、ガベージコレクションされることを保証します。また、アプリケーションを素早く終了するには、android.os.Process.killProcess(android.os.Process.myPid())必要に応じて、これを行う最善の方法は、次のようなメソッドをヘルパー クラスに配置し、アプリを強制終了する必要があるときにいつでも呼び出すことです。たとえば、ルート アクティビティの destroy メソッドで次のようにします (アプリがこのアクティビティを強制終了しないことを前提としています)。
また、Androidはアプリケーションに通知しません家キーイベントが発生するため、家キーが押されたときにAndroidは家キーイベントを自分自身に設定することで、開発者がユーザーがアプリケーションを離れるのを防ぐことができなくなります。ただし、家キーが押されたかどうかは、ヘルパークラスでフラグをtrueに設定することで確認できる。家キーが押されたことを示すイベントが発生したときにフラグをfalseに変更します。家キーが押されていないことを確認してから家キーが押されたオンストップ()活動の方法。
忘れずに処理してください家キーはメニューやメニューから開始されるアクティビティで使用できます。検索キー。以下に、説明のためのクラスの例をいくつか示します。
以下は、アプリケーションが破棄されたときにアプリケーションを強制終了するルート アクティビティの例です。
package android.example;
/**
* @author Danny Remington - MacroSolve
*/
public class HomeKey extends CustomActivity {
public void onDestroy() {
super.onDestroy();
/*
* Kill application when the root activity is killed.
*/
UIHelper.killApp(true);
}
}
これは、次のような処理を拡張できる抽象アクティビティです。家それを拡張するすべてのアクティビティのキー:
package android.example;
/**
* @author Danny Remington - MacroSolve
*/
import android.app.Activity;
import android.view.Menu;
import android.view.MenuInflater;
/**
* Activity that includes custom behavior shared across the application. For
* example, bringing up a menu with the settings icon when the menu button is
* pressed by the user and then starting the settings activity when the user
* clicks on the settings icon.
*/
public abstract class CustomActivity extends Activity {
public void onStart() {
super.onStart();
/*
* Check if the app was just launched. If the app was just launched then
* assume that the HOME key will be pressed next unless a navigation
* event by the user or the app occurs. Otherwise the user or the app
* navigated to this activity so the HOME key was not pressed.
*/
UIHelper.checkJustLaunced();
}
public void finish() {
/*
* This can only invoked by the user or the app finishing the activity
* by navigating from the activity so the HOME key was not pressed.
*/
UIHelper.homeKeyPressed = false;
super.finish();
}
public void onStop() {
super.onStop();
/*
* Check if the HOME key was pressed. If the HOME key was pressed then
* the app will be killed. Otherwise the user or the app is navigating
* away from this activity so assume that the HOME key will be pressed
* next unless a navigation event by the user or the app occurs.
*/
UIHelper.checkHomeKeyPressed(true);
}
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.settings_menu, menu);
/*
* Assume that the HOME key will be pressed next unless a navigation
* event by the user or the app occurs.
*/
UIHelper.homeKeyPressed = true;
return true;
}
public boolean onSearchRequested() {
/*
* Disable the SEARCH key.
*/
return false;
}
}
以下は、次のようなメニュー画面の例です。家鍵：
/**
* @author Danny Remington - MacroSolve
*/
package android.example;
import android.os.Bundle;
import android.preference.PreferenceActivity;
/**
* PreferenceActivity for the settings screen.
*
* @see PreferenceActivity
*
*/
public class SettingsScreen extends PreferenceActivity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.layout.settings_screen);
}
public void onStart() {
super.onStart();
/*
* This can only invoked by the user or the app starting the activity by
* navigating to the activity so the HOME key was not pressed.
*/
UIHelper.homeKeyPressed = false;
}
public void finish() {
/*
* This can only invoked by the user or the app finishing the activity
* by navigating from the activity so the HOME key was not pressed.
*/
UIHelper.homeKeyPressed = false;
super.finish();
}
public void onStop() {
super.onStop();
/*
* Check if the HOME key was pressed. If the HOME key was pressed then
* the app will be killed either safely or quickly. Otherwise the user
* or the app is navigating away from the activity so assume that the
* HOME key will be pressed next unless a navigation event by the user
* or the app occurs.
*/
UIHelper.checkHomeKeyPressed(true);
}
public boolean onSearchRequested() {
/*
* Disable the SEARCH key.
*/
return false;
}
}
以下は、次の処理を実行するヘルパークラスの例です。家アプリ全体のキー:
package android.example;
/**
* @author Danny Remington - MacroSolve
*
*/
/**
* Helper class to help handling of UI.
*/
public class UIHelper {
public static boolean homeKeyPressed;
private static boolean justLaunched = true;
/**
* Check if the app was just launched. If the app was just launched then
* assume that the HOME key will be pressed next unless a navigation event
* by the user or the app occurs. Otherwise the user or the app navigated to
* the activity so the HOME key was not pressed.
*/
public static void checkJustLaunced() {
if (justLaunched) {
homeKeyPressed = true;
justLaunched = false;
} else {
homeKeyPressed = false;
}
}
/**
* Check if the HOME key was pressed. If the HOME key was pressed then the
* app will be killed either safely or quickly. Otherwise the user or the
* app is navigating away from the activity so assume that the HOME key will
* be pressed next unless a navigation event by the user or the app occurs.
*
* @param killSafely
* Primitive boolean which indicates whether the app should be
* killed safely or quickly when the HOME key is pressed.
*
* @see {@link UIHelper.killApp}
*/
public static void checkHomeKeyPressed(boolean killSafely) {
if (homeKeyPressed) {
killApp(true);
} else {
homeKeyPressed = true;
}
}
/**
* Kill the app either safely or quickly. The app is killed safely by
* killing the virtual machine that the app runs in after finalizing all
* {@link Object}s created by the app. The app is killed quickly by abruptly
* killing the process that the virtual machine that runs the app runs in
* without finalizing all {@link Object}s created by the app. Whether the
* app is killed safely or quickly the app will be completely created as a
* new app in a new virtual machine running in a new process if the user
* starts the app again.
*
* <P>
* <B>NOTE:</B> The app will not be killed until all of its threads have
* closed if it is killed safely.
* </P>
*
* <P>
* <B>NOTE:</B> All threads running under the process will be abruptly
* killed when the app is killed quickly. This can lead to various issues
* related to threading. For example, if one of those threads was making
* multiple related changes to the database, then it may have committed some
* of those changes but not all of those changes when it was abruptly
* killed.
* </P>
*
* @param killSafely
* Primitive boolean which indicates whether the app should be
* killed safely or quickly. If true then the app will be killed
* safely. Otherwise it will be killed quickly.
*/
public static void killApp(boolean killSafely) {
if (killSafely) {
/*
* Notify the system to finalize and collect all objects of the app
* on exit so that the virtual machine running the app can be killed
* by the system without causing issues. NOTE: If this is set to
* true then the virtual machine will not be killed until all of its
* threads have closed.
*/
System.runFinalizersOnExit(true);
/*
* Force the system to close the app down completely instead of
* retaining it in the background. The virtual machine that runs the
* app will be killed. The app will be completely created as a new
* app in a new virtual machine running in a new process if the user
* starts the app again.
*/
System.exit(0);
} else {
/*
* Alternatively the process that runs the virtual machine could be
* abruptly killed. This is the quickest way to remove the app from
* the device but it could cause problems since resources will not
* be finalized first. For example, all threads running under the
* process will be abruptly killed when the process is abruptly
* killed. If one of those threads was making multiple related
* changes to the database, then it may have committed some of those
* changes but not all of those changes when it was abruptly killed.
*/
android.os.Process.killProcess(android.os.Process.myPid());
}
}
}