求指教：练习viewSwitcher时出错，找了半天不知道哪里出错了

Question

androidviewSwither

Answer 1

R.layout.activity_main:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
     >    <ViewSwitcher
        android:id="@+id/viewSwither"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        />
    
    <Button
        android:id="@+id/button_pre"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="prev"
        android:text="@string/pre"
        />    <Button
        android:id="@+id/button_next"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="next"
        android:text="@string/next"
        /> </RelativeLayout>R.layout.slidelistview
<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gridView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:verticalSpacing="5dp"
    android:gravity="center" 
    android:stretchMode="spacingWidth"
    android:numColumns="4">
  </GridView>R.layout.lableicon.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center" >
    
    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />"
    </LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.learning.viewswitchertest"
    android:versionCode="1"
    android:versionName="1.0" >    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="20" />    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application></manifest>

Answer 2

不是报了NullPointer 控制真错误吗？应该是你有变量没有初始化就直接用了，你点Logcat中的日志，跳转到错误位置就知道了12-26 14:54:45.214: E/AndroidRuntime(615): FATAL EXCEPTION: main
12-26 14:54:45.214: E/AndroidRuntime(615): java.lang.NullPointerException
12-26 14:54:45.214: E/AndroidRuntime(615):  at com.learning.viewswitchertest.MainActivity$1.getView(MainActivity.java:97)

Answer 3

应该是这里错了:
 private BaseAdapter adapter = new BaseAdapter() {               //动态Adapter
         
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            View view = convertView ;
            if(convertView == null){
                view = inflater.inflate(R.layout.lableicon, null);  //  元素是name和drawable的线性布局lableicon
            }
             
            ImageView imageView = (ImageView) view .findViewById(R.id.imageView);
            TextView textView = (TextView) view .findViewById(R.id.textView); 
            imageView.setImageDrawable(getItem(position).drawable);
            textView.setText(getItem(position).dataName);
             
            return view;
        }
         
        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return position;
        }
         
        @Override
        public DataItem getItem(int position) {
            // TODO Auto-generated method stub
        return items.get(screenNum * NUM_PER_SCREEN + position);
 
        }
         
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            if(screenNum == screenCount-1 && items.size() % NUM_PER_SCREEN != 0 )
                return items.size() % NUM_PER_SCREEN ;
            return NUM_PER_SCREEN; 
        }
    };
}

Answer 4

定位到 原代码的97行：imageView.setImageDrawable(getItem(position).drawable);
其中drawable在 现在的第23行 for循环中已经初始化了，还是找不到错

Answer 5

不好意思啊，之前看得太快没看出你加的View
现在程序可以跑起来了但是gridView没有加载出图标，界面只有两个button，怀疑adapter中有问题，能帮我看看么谢谢

Answer 6

不好意思啊，之前看得太快没看出你加的View
现在程序可以跑起来了但是gridView没有加载出图标，界面只有两个button，怀疑adapter中有问题，能帮我看看么谢谢
也没有报错

Answer 7

没加载出图标你要确认你你的imageview是否有设置成功，跟日志看看。需要具体调试才知道是什么问题