Question

我正在尝试从BroadcastReceiver获取字符串，该字符串将在我的活动中设置TextView的内容。

我有两个Java类

MainActivity：它有TextView我想要更改的文本。
batteryinfo：它扩展了BroadcastReceiver。这个班有返回自定义String（getString（））

以下是MainActivity的代码

package com.example.batteryhealth;

import android.app.Activity;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

    BatteryManager bm;
    TextView health;
    String string;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        health=(TextView)findViewById(R.id.textView1);
        //status=(TextView)findViewById(R.id.textView2);
        batteryinfo bmc= new batteryinfo(bm,string);
        this.registerReceiver(bmc, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

        health.setText(bmc.gethealth());


    }

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

    }

以下是batteryinfo的代码：

package com.example.batteryhealth;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.BatteryManager;

public class batteryinfo extends BroadcastReceiver{

    BatteryManager bm;
    String health;

    public batteryinfo(BatteryManager b,String hea) {
        // TODO Auto-generated constructor stub

        this.bm=b;
        this.health=hea;

    }




    @Override
    public void onReceive(Context arg0, Intent intent) {
        // TODO Auto-generated method stub
    int i= intent.getIntExtra(bm.EXTRA_HEALTH, 0);

        boolean s=true;


        if(s=i==bm.BATTERY_HEALTH_COLD)
        {
           health="cold";

        }
        else if(s=i==bm.BATTERY_HEALTH_GOOD)
        {
            health="good";
        }
        else if (s=i==bm.BATTERY_HEALTH_OVERHEAT)

        {
            health="overheat"       ;
        }
        else if (s=i==bm.BATTERY_HEALTH_OVER_VOLTAGE)
        {
            health="overvolteage";
        }

    }

    public String gethealth()
    {
        return health;
    }

}

如果我在MainActivity中创建一个嵌套类（也扩展了BroadcastReciver），代码工作正常，但在创建一个单独的类后它不起作用，我的TextView为空。

Answer 1

在MainActivity中注册新的广播接收器，然后从您的batteryinfo类向MainActivity类发送广播，并更改MainActivity接收器中的文本

无法从BroadcastReceiver更改TextView内容

1 个答案: