在标签中画线

Question

我想在第二个标签中画一些线条，但是我有错误“...意外停止”。也许有人可以帮助...

tab_map.xml

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout 
    android:id="@+id/map_view" 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:background="#FFFFFF" /> 

TabMap.java

public class TabMap extends Activity { 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.tab_map); 

     FrameLayout fLayout = (FrameLayout) findViewById(R.id.map_view); 
     fLayout.addView(new TabMapLine(this, 0, 0, 50, 50)); 
    } 

TabMapLine.java

public class TabMapLine extends View{ 

    private final float startX; 
    private final float stopX; 
    private final float startY; 
    private final float stopY; 
    Paint paint = new Paint(); 

    public TabMapLine(Context context, float x1, float y1,float x2, float y2){ 
     super(context); 
     paint.setColor(0xFFFF0000); 
     this.startX = x1; 
     this.startY = y1; 
     this.stopX = x2; 
     this.stopY = y2; 
    } 

    protected void onDraw(Canvas canvas){ 
     super.onDraw(canvas); 
     canvas.drawLine(startX, startY, stopX, stopY, paint); 
    } 
} 

TabActivity：Training.java

public class Training extends TabActivity { 

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main_training); 

    Resources res = getResources(); 
    TabHost tabHost = getTabHost(); 
    TabHost.TabSpec spec1; 
    TabHost.TabSpec spec2; 
    Intent intent1; 
    Intent intent2; 

    intent1 = new Intent().setClass(this, TabTimer.class); 

    spec1 = tabHost.newTabSpec("tab1").setIndicator("Tren", 
      res.getDrawable(R.drawable.tab_1)).setContent(intent1); 
    tabHost.addTab(spec1); 

    intent2 = new Intent().setClass(this, TabMap.class); 
    spec2 = tabHost.newTabSpec("tab2").setIndicator("Map", 
      res.getDrawable(R.drawable.tab_2)).setContent(intent2); 
    tabHost.addTab(spec2); 

    tabHost.setCurrentTab(0); 
} 

}

登录猫错误

E/AndroidRuntime(2472):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
E/AndroidRuntime(2472):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
E/AndroidRuntime(2472):at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
E/AndroidRuntime(2472):at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
E/AndroidRuntime(2472):at android.os.Handler.dispatchMessage(Handler.java:99) 
E/AndroidRuntime(2472):at android.os.Looper.loop(Looper.java:123) 
E/AndroidRuntime(2472):at android.app.ActivityThread.main(ActivityThread.java:4627) 
E/AndroidRuntime(2472):at java.lang.reflect.Method.invokeNative(Native Method) 
E/AndroidRuntime(2472):at java.lang.reflect.Method.invoke(Method.java:521) 
E/AndroidRuntime(2472):at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
E/AndroidRuntime(2472):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
E/AndroidRuntime(2472):at dalvik.system.NativeStart.main(Native Method) 
E/AndroidRuntime(2472):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
E/AndroidRuntime(2472):at android.app.ActivityThread.startActivityNow(ActivityThread.java:2503) 
E/AndroidRuntime(2472):at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127) 
E/AndroidRuntime(2472):at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339) 
E/AndroidRuntime(2472):at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:651) 
E/AndroidRuntime(2472):at android.widget.TabHost.setCurrentTab(TabHost.java:323) 
E/AndroidRuntime(2472):at android.widget.TabHost.addTab(TabHost.java:213) 
E/AndroidRuntime(2472):at org.me.piana.training.Training.onCreate(Train 
ing.java:39) 
E/AndroidRuntime(2472):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
E/AndroidRuntime(2472):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
E/AndroidRuntime(2472):... 11 more 
E/AndroidRuntime(2472): Caused by: java.lang.ClassCastException: android.widget.TextView 
E/AndroidRuntime(2472):at org.me.piana.training.TabTimer.onCreate(TabTimer.java:59) 
E/AndroidRuntime(2472):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
E/AndroidRuntime(2472):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
E/AndroidRuntime(2472):  ... 20 more 
W/ActivityManager(58):Force finishing activity org.me.piana/.training.Training 
W/ActivityManager( 58):Force finishing activity org.me.piana/.PIaNA 
W/ActivityManager( 58):Activity pause timeout for HistoryRecord{45114d10 org.me.piana/.training.Training} 
D/SntpClient( 58): request time failed: java.net.SocketException: Address fami 
ly not supported by protocol 
W/ActivityManager( 58): Activity destroy timeout for HistoryRecord{45080400 or 
g.me.piana/.PIaNA} 
W/ActivityManager( 58): Activity destroy timeout for HistoryRecord{45114d10 or 
g.me.piana/.training.Training} 

Answer 1

，我可以从日志输出看，问题出在TabTimeronCreate()方法。您试图在TabTimer.java的第59行将TextView对象转换为错误类型