主体思想
使用ActivityCollector来收集所有活动，所有的活动均继承自BaseActivity，使得每个活动在onCreate方法执行时，都会被加入到AcrivityCollector中。在每个活动onDestroy时都会从ActivityCollector中移除。这样就可以一次性将所有的活动全部销毁。在登陆界面输入账号密码，代码的设定是只有当敲击Login按钮时才会去获取两个EditText中，符合逻辑
交互的流程是，输入账号密码，无误后跳转到MainActivity，点击按钮发送广播，app中的recreiver接收到广播执行onReceive方法，弹出AlertDialog窗口，给ok按钮设置监听。按下ok之后，用ActivityCollector销毁所有活动，重新加载login活动
值得注意
因为是从接收器中弹出活动，intent需加入FLAG_ACTIVITY_NEW_TASK，形如intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),在接受器里启动活动，需以这样的格式：context.startActivity(intent),而intent的初始化是以这样的形式：Intent intent = new Intent(context,MainActivity.class),似乎在接收器里都用context来表示接收器的上下文
再有，因为提示框是从广播接收器中弹出的，所以需要把对话框的类型设置为TYPE_SYSTEM_ALERT，形如：alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT),由于都调用了系统级别的对话框，也需要在Manifest文件下注册<user-permission android:name="android.permission.SYSTEM_ALERT_WINDOW">,该应用才能使用该对话框
另外需要注意的是，AlertDialog的造法：
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AlertDialog.Builder builder = new AlertDialog.Builder(context)
builder.setTitle
builder.setMessage
builder.setPositiveButton("OK",new OnclickListener{....})
AlertDialog alertDialog = builder.create();
alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT)
alertDialog.show()
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先弄个builder，再用这个builder去建一个AlertDialog，接着再设置这个AlertDialog的类型，最后让他show出来
代码结构
代码结构
上代码
ActivityCollector.class
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public class ActivityCollector {
public static List<Activity> activities = new ArrayList<Activity>();
public static void addActivity(Activity activity){
activities.add(activity);
}
public static void removeActivity(Activity activity){
activities.remove(activity);
}
public static void finishAll(){
for(Activity activity : activities){
if(!activity.isFinishing()){
activity.finish();
}
}
}
}
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BaseActivity.class
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public class BaseActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityCollector.addActivity(this);
}
@Override
protected void onDestroy() {
super.onDestroy();
ActivityCollector.removeActivity(this);
}
}
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forceReceiver.class
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public class ForceOffReceiver extends BroadcastReceiver{
@Override
public void onReceive(final Context context, final Intent intent) {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Waring");
builder.setCancelable(false);
builder.setMessage("you are forced to offline");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ActivityCollector.finishAll();
Intent intent1 = new Intent(context,loginActivity.class);
intent1.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent1);
}
});
AlertDialog alertDialog = builder.create();
alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
alertDialog.show();
}
}
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loginActivity.class
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public class loginActivity extends BaseActivity {
EditText accountEdit;
EditText passwordEdit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
accountEdit = (EditText) findViewById(R.id.content_account);
passwordEdit = (EditText) findViewById(R.id.content_password);
Button btn = (Button) findViewById(R.id.btn_login);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String account = accountEdit.getText().toString();
String password = passwordEdit.getText().toString();
if(account.equals("guojiale") && password.equals("123456")){
Intent intent = new Intent(loginActivity.this,MainActivity.class);
startActivity(intent);
} else{
Toast.makeText(loginActivity.this, "Check your account and password", Toast.LENGTH_SHORT).show();
}
}
});
}
}
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MainActivity.class
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public class MainActivity extends BaseActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.btn_sendBrodcast);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("forceOff");
sendBroadcast(intent);
}
});
}
}
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零散笔记
广播接收器中不允许开线程，如果广播接收器中有太多操作，耗时太长，程序会报错
在一个应用的Manifest文件中，配置
使得该应用获得监听系统开机广播的权限，在中，写 rr这是在注册监听器
在manifest中receiver（接收器）的intent-filter中的action是表示该接收器监听的广播类型一旦收到相应类型的广播，就会执行该接收器中的逻辑
在一个活动中发送广播，sendBroadcast为发送标准广播,sendOrderedBroadcast为发送有序广播，在Manifest文件下配置receiver需要的intentFilter,用priority来判断接收器的接收顺序
使用abortBroadcast() 截断广播
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LocalBroadcastManager l = LocalBraodcastManager.getInstace(this)
l.registerReceiver(localReceiver,intentFilter);
l.sendBroadcast(intent)
l.unregisterReceiver(localReceiver)
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抛出异常：
java.lang.RuntimeException: Unable to start receiver com.example.gaby.broadcastbestpractice.ForceOffReceiver: android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@d5bf998 – permission denied for this window type
原因：使用了系统级别的对话框，但没有在Manifest文件下声明该权限
解决办法:在Manifest文件下声明< user-permission android:name=”android.permission.SYSTEM_ALERT_WINDOW” />
