Question

我在Android应用程序中使用了TabActivity。一切正常，但以下情况除外：

我使用主页按钮
我关闭手机（待机模式）
过了一会儿我打开手机，我想回到我的应用程序
应用程序崩溃并出现NullPointerException

更多信息：我认为这是因为我使用AsyncTask，此外Webview和应用程序无法恢复最后一个状态，但我该如何解决？ AsynTask在onCreate（）中触发。我也使用Webview。

一个解决方案可能是每次用户点击后面或主页按钮时杀死整个应用程序，但这不是真正用户友好。有人知道另一种选择吗？

import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.TabHost;
import android.widget.TextView;



public class BBGMainActivity extends TabActivity {
    /** Called when the activity is first created. */

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.bbg_main);
        setTabs() ;
    }

    private void setTabs()
    {
        addTab("News", R.drawable.tab_news, BBGWebViewActivity.class, "http://www.google.com");     
        addTab("Intern", R.drawable.tab_home, BBGPDFViewerActivity.class, "");      
        addTab("Offers", R.drawable.tab_offer, BBGWebViewWithHeaderActivity.class, "http://www.google.com");
        addTab("Service", R.drawable.tab_service, BBGJSONParsingActivity.class, "");
        addTab("Office", R.drawable.tab_offices, BBGListViewActivity.class, "");
    }


    private void addTab(String labelId, int drawableId, Class<?> c, String url)
    {
        TabHost tabHost = getTabHost();
        //tabHost.setup();
        Intent intent = new Intent(this, c);
        intent.putExtra("URL",url);
        TabHost.TabSpec spec = tabHost.newTabSpec("tab" + labelId); 

        View tabIndicator = LayoutInflater.from(this).inflate(R.layout.tab_indicator, getTabWidget(), false);
        TextView title = (TextView) tabIndicator.findViewById(R.id.title);
        title.setText(labelId);
        ImageView icon = (ImageView) tabIndicator.findViewById(R.id.icon);
        icon.setImageResource(drawableId);

        spec.setIndicator(tabIndicator);
        spec.setContent(intent);
        tabHost.addTab(spec);
    }

    @Override
    public void onResume() {
        super.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
    }
}

错误日志：

06-28 09:22:02.445: E/AndroidRuntime(32549): FATAL EXCEPTION: main
06-28 09:22:02.445: E/AndroidRuntime(32549): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.bbg/org.bbg.BBGMainActivity}: java.lang.RuntimeException: Unable to start activity ComponentInfo{org.bbg/org.bbg.BBGWebViewActivity}: java.lang.NullPointerException
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.access$1500(ActivityThread.java:135)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.os.Looper.loop(Looper.java:150)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.main(ActivityThread.java:4385)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at java.lang.reflect.Method.invokeNative(Native Method)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at java.lang.reflect.Method.invoke(Method.java:507)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at dalvik.system.NativeStart.main(Native Method)
06-28 09:22:02.445: E/AndroidRuntime(32549): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{org.bbg/org.bbg.BBGWebViewActivity}: java.lang.NullPointerException
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1872)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.startActivityNow(ActivityThread.java:1692)
06-28 09:21:44.557: D/dalvikvm(32384): GC_EXTERNAL_ALLOC freed 12K, 46% free 3148K/5767K, external 569K/583K, paused 228ms
06-28 09:22:02.445: D/AndroidRuntime(32549): Shutting down VM
06-28 09:22:02.445: W/dalvikvm(32549): threadid=1: thread exiting with uncaught exception (group=0x4001d5a0)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:656)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.widget.TabHost.setCurrentTab(TabHost.java:326)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.widget.TabHost.addTab(TabHost.java:216)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at org.bbg.BBGMainActivity.addTab(BBGMainActivity.java:53)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at org.bbg.BBGMainActivity.setTabs(BBGMainActivity.java:28)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at org.bbg.BBGMainActivity.onCreate(BBGMainActivity.java:23)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
06-28 09:22:02.445: E/AndroidRuntime(32549):    ... 11 more
06-28 09:22:02.445: E/AndroidRuntime(32549): Caused by: java.lang.NullPointerException
06-28 09:22:02.445: E/AndroidRuntime(32549):    at org.bbg.BBGWebViewActivity.onCreate(BBGWebViewActivity.java:61)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
06-28 09:22:02.445: E/AndroidRuntime(32549):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
06-28 09:22:02.445: E/AndroidRuntime(32549):    ... 22 more

从Sleep / StandbyMode返回时TabActivity出错

0 个答案: