Android开发中如何在Activity内调用嵌套类方法并绑定到按钮事件

已存在的错误点 #

• 类名使用错误：你定义的广播接收器类为StateReceiver，但实例化时使用了不存在的类名PhoneStateBroadcastReceiver
• 非静态内部类实例化规则错误：代码中的PhoneStateListener是StateReceiver的非静态内部类，必须依赖外部类实例才能完成实例化
• 缺少权限与注册逻辑：监听电话状态需要申请READ_PHONE_STATE权限，同时需要动态注册广播、绑定电话状态监听服务，否则逻辑不会生效

按钮点击事件中的完整实现 #

import android.Manifest;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.content.IntentFilter;

// 类内全局变量
private StateReceiver stateReceiver;
private StateReceiver.PhoneStateListener phoneStateListener;

// 按钮点击逻辑
findViewById(R.id.你的按钮ID).setOnClickListener(v -> {
    // 权限校验（Android 6.0及以上必须动态申请）
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_PHONE_STATE}, 1001);
        return;
    }

    // 实例化外部类
    stateReceiver = new StateReceiver();
    // 实例化非静态内部类，必须通过外部类实例调用
    phoneStateListener = stateReceiver.new PhoneStateListener();

    // 注册广播接收器
    IntentFilter filter = new IntentFilter(TelephonyManager.ACTION_PHONE_STATE_CHANGED);
    registerReceiver(stateReceiver, filter);

    // 绑定电话状态监听
    TelephonyManager telephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
    telephonyManager.listen(phoneStateListener, PhoneStateListener.LISTEN_CALL_STATE);
});

// Activity销毁时注销监听，避免内存泄漏
@Override
protected void onDestroy() {
    super.onDestroy();
    if (stateReceiver != null) {
        unregisterReceiver(stateReceiver);
    }
    if (phoneStateListener != null) {
        TelephonyManager telephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
        telephonyManager.listen(phoneStateListener, PhoneStateListener.LISTEN_NONE);
    }
}

可选优化 #

如果PhoneStateListener不需要访问StateReceiver的非静态成员，可将其改为静态内部类，无需依赖外部类实例即可实例化：

public class StateReceiver extends BroadcastReceiver {
    public void method1(Context context, Intent intent){
        // 广播接收逻辑
    }

    // 添加static修饰改为静态内部类
    public static class PhoneStateListener extends PhoneStateListener {
        public void method2 (int var, String var2) {
            // 电话状态变化处理逻辑
        }
    }
}

静态内部类实例化代码：
StateReceiver.PhoneStateListener phoneStateListener = new StateReceiver.PhoneStateListener();

内容的提问来源于stack exchange，提问作者Exkrasos