创建AcitivityCollector类
管理所有活动
public class ActivityCollector {
public static List<Activity> activities = new ArrayList<>();
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(!activities.isEmpty()){
activity.finish();
}
}
}
}
创建BaseActivity作为所有活动父类
public class BaseActivity extends AppCompatActivity {
private ForceOffLineReceiver receiver;
@Override
protected void onResume() {
super.onResume();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("com.example.broadcastbestpractice.FORCE_OFFLINE");
receiver = new ForceOffLineReceiver();
registerReceiver(receiver,intentFilter);
}
@Override
protected void onPause() {
super.onPause();
if(receiver!=null){
unregisterReceiver(receiver);
receiver = null;
}
}
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityCollector.addActivity(this);
}
@Override
protected void onDestroy() {
super.onDestroy();
ActivityCollector.removeActivity(this);
}
class ForceOffLineReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Warning");
builder.setMessage("You are forced to be offline");
builder.setCancelable(false);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
ActivityCollector.finishAll();
Intent intent = new Intent(context,LoginActivity.class);
context.startActivity(intent);
}
});
builder.show();
}
}
}
ForceOfflineReceiver
- 使用AlertDialog.Builder来构建一个对话框
- 调用setCancelable()方法将对话框设置为不可取消
- 调用setPositiveButton()方法来给对话框注册确定按钮
修改LoginActivity类
public class LoginActivity extends BaseActivity {
private EditText accountEdit;
private EditText passwordEdit;
private Button login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
accountEdit = findViewById(R.id.account);
passwordEdit = findViewById(R.id.password);
login = findViewById(R.id.login);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String account = accountEdit.getText().toString();
String password = passwordEdit.getText().toString();
//密码是123456.用户名为admin
if(account.equals("admin")&&password.equals("123456")){
Intent intent = new Intent(LoginActivity.this,MainActivity.class);
startActivity(intent);
finish();
}else{
Toast.makeText(LoginActivity.this,"account or password is invalid",Toast.LENGTH_SHORT).show();
}
}
});
}
}
修改MainActivity中的代码
public class MainActivity extends BaseActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button forceOffline = findViewById(R.id.force_offline);
forceOffline.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent("com.example.broadcastbestpractice.FORCE_OFFLINE");
sendBroadcast(intent);
}
});
}
}