Question

使用两项活动。如果我想做一些事情，比如检查互联网连接并用结果更新另一个活动，当我进入第一个活动的线程时，如何让StatusMessage显示在Textview中的第二个活动布局上...现在，文本在第二个活动的textview上没有变化。如果我需要从第一个启动的第二个活动中引用一个属性，我该怎么做？

Second Activity: 

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.TextView;


public class CopyOfSplash extends Activity {
protected boolean _active = true;
protected int _splashTime = 15000;
TextView mainText;
String statusMessage;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.splash);

    Thread splashTread = new Thread() {
        @Override
        public void run() {
            try {

                ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);    
                NetworkInfo netInfo = cm.getActiveNetworkInfo();    
                if (netInfo.isConnected()) 
                {
                     statusMessage= "Connected to the internet!";
                }   
                else
                {
                    statusMessage = "User is probably in airplane mode!";           
                }




            } catch(InterruptedException e) {
                // do nothing
            } finally {
                finish();
                startActivity(new Intent("com.nwp.Main")); 
               runOnUiThread(new Runnable() {
                    @Override
    public void run() {               
                        setContentView(R.layout.main);
                  mainText = (TextView) findViewById(R.id.mainTextView);
           mainText.setText(statusMessage);
            }        

             });

                stop();

            }
        }
    };

    splashTread.start();
}


@Override
public boolean onTouchEvent(MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        _active = false;
    }
    return true;
}
}


First Activity:

public class Main extends Activity {


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


  }
}

Manifest File:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.nwp" android:versionCode="1" android:versionName="1.0">
<uses-sdk android:minSdkVersion="7" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application android:icon="@drawable/icon" 
android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"   android:label="@string/app_name">
    <activity android:name=".Splash"
              android:label="@string/app_name"   
              android:screenOrientation="landscape" 
              android:configChanges="keyboardHidden|orientation" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name="com.nwp.Main" 
              android:screenOrientation="landscape" 
              android:configChanges="keyboardHidden|orientation">
        <intent-filter>
            <action android:name="com.nwp.Main" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
</application>

Answer 1

为什么不在第二个活动的TextView方法中移动onCreate更改代码？要调用findViewById()，您需要将TextView的父布局设置为当前展示活动的内容视图，否则findViewById()将返回null。

Android：更新线程内活动的Textview

1 个答案: