Java 在ViewSwitcher中在不确定进度条和图像之间切换
尝试使用viewSwitcher在ProgressBar和图像之间切换时,我收到以下错误:Java 在ViewSwitcher中在不确定进度条和图像之间切换,java,android,xml,components,Java,Android,Xml,Components,尝试使用viewSwitcher在ProgressBar和图像之间切换时,我收到以下错误: 07-30 18:08:00.627: ERROR/AndroidRuntime(307): Caused by: java.lang.NullPointerException 07-30 18:08:00.627: ERROR/AndroidRuntime(307): at android.view.ViewGroup.addView(ViewGroup.java:1815) 07-30 18:
07-30 18:08:00.627: ERROR/AndroidRuntime(307): Caused by: java.lang.NullPointerException
07-30 18:08:00.627: ERROR/AndroidRuntime(307): at android.view.ViewGroup.addView(ViewGroup.java:1815)
07-30 18:08:00.627: ERROR/AndroidRuntime(307): at android.view.ViewGroup.addView(ViewGroup.java:1802)
07-30 18:08:00.627: ERROR/AndroidRuntime(307): at com.romcessed.romsearch.activities.RomDetailActivity$LoadImageViewsTask.intializeSwitchers(RomDetailActivity.java:161)
以下是导致错误的代码:
//Place indeterminate progress bars for our ImageViews until computation is complete
switcherTask = new LoadImageViewsTask();
switcherTask.intializeSwitchers();
switcherTask.execute((Void) null);
.
..
...
void intializeSwitchers(){
captchaSwitcher = new ViewSwitcher(RomDetailActivity.this);
gallerySwitcher = new ViewSwitcher(RomDetailActivity.this);
/*Line that caused error */
captchaSwitcher.addView((ProgressBar)findViewById(R.layout.indeter));
/* */
gallerySwitcher.addView(findViewById(R.layout.indeter));
captchaSwitcher.addView(iv_Captcha);
gallerySwitcher.addView(gal_Screenshots);
}
以下是indeter.xml:
<?xml version="1.0" encoding="utf-8"?>
<ProgressBar
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/progressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true" />
基本上,您需要使用布局充气器对视图进行充气,然后将其添加到切换器中,或者您也可以根据代码创建新视图 有关基本布局充气机功能,请参见此链接: