如何设置setLayoutParams线性布局元素 [英] how to set setLayoutParams for linear layout elements
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问题描述
大家好 如何设置setLayoutParams线性布局元素。在mainactivity我写了下面$ C $下设置布局PARAMS和空指针异常在该行没有50所示我粘贴文件的logcat最后。
的LayoutParams =新LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,50);
imageview1.setLayoutParams(的LayoutParams); //行没有50
的LayoutParams =新LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,50);
textview1.setLayoutParams(的LayoutParams);
的LayoutParams =新LinearLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT);
listview01.setLayoutParams(的LayoutParams);
这是我的xml文件
< XML版本=1.0编码=UTF-8&GT?;
< LinearLayout中的xmlns:机器人=http://schemas.android.com/apk/res/android
机器人:方向=垂直
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =WRAP_CONTENT
机器人:stackFromBottom =真
>
< ImageView的
机器人:ID =@ + ID / imageview1
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =50像素
机器人:背景=@可绘制/ applicationbar
机器人:layout_x =0px
机器人:layout_y =0px
>
< / ImageView的>
<的TextView
机器人:ID =@ + ID / textview1
机器人:layout_width =WRAP_CONTENT
机器人:layout_height =50像素
机器人:文本=TextView的
机器人:layout_x =0px
机器人:layout_y =55像素
>
< / TextView的>
< ListView的机器人:ID =@ + ID / ListView01
机器人:layout_width =FILL_PARENT
机器人:layout_height =WRAP_CONTENT
机器人:layout_marginLeft =10px的
机器人:layout_marginRight =10px的
机器人:layout_marginTop =35px
机器人:layout_marginBottom =40PX
机器人:以下属性来=0px
机器人:paddingRight =0px/>
< / LinearLayout中>
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04-19 16:47:22.221:ERROR / AndroidRuntime(3437):未捕获的处理程序:螺纹主力退出,由于未捕获的异常
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):java.lang.RuntimeException的:无法启动的活动ComponentInfo {com.android/com.android.Listview}:显示java.lang.NullPointerException
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread.access $ 2200(ActivityThread.java:119)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1863)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.os.Handler.dispatchMessage(Handler.java:99)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.os.Looper.loop(Looper.java:123)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread.main(ActivityThread.java:4363)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在java.lang.reflect.Method.invokeNative(本机方法)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在java.lang.reflect.Method.invoke(Method.java:521)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:860)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在dalvik.system.NativeStart.main(本机方法)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):由:显示java.lang.NullPointerException
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在com.android.Listview.onCreate(Listview.java:40)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-19 16:47:22.221:ERROR / AndroidRuntime(3437):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
请帮我。
解决方案
imageview1.setLayoutParams(新的LayoutParams(LayoutParams.WRAP_CONTENT,50));
textview1.setLayoutParams(新的LayoutParams(LayoutParams.WRAP_CONTENT,50));
listview01.setLayoutParams(新
的LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
hi all how to set setLayoutParams for linear layout elements. in mainactivity i wrote the following code for set Layout params and null pointer exception shown at the line no 50 and i paste Logcat file at last.
layoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, 50);
imageview1.setLayoutParams(layoutParams); // line no 50
layoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, 50);
textview1.setLayoutParams(layoutParams);
layoutParams = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT);
listview01.setLayoutParams(layoutParams);
this is my xml file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:stackFromBottom="true"
>
<ImageView
android:id="@+id/imageview1"
android:layout_width="wrap_content"
android:layout_height="50px"
android:background="@drawable/applicationbar"
android:layout_x="0px"
android:layout_y="0px"
>
</ImageView>
<TextView
android:id="@+id/textview1"
android:layout_width="wrap_content"
android:layout_height="50px"
android:text="TextView"
android:layout_x="0px"
android:layout_y="55px"
>
</TextView>
<ListView android:id="@+id/ListView01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="10px"
android:layout_marginRight="10px"
android:layout_marginTop="35px"
android:layout_marginBottom="40px"
android:paddingLeft="0px"
android:paddingRight="0px" />
</LinearLayout>
Log cat:
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): Uncaught handler: thread main exiting due to uncaught exception
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android/com.android.Listview}: java.lang.NullPointerException
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.os.Handler.dispatchMessage(Handler.java:99)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.os.Looper.loop(Looper.java:123)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread.main(ActivityThread.java:4363)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at java.lang.reflect.Method.invokeNative(Native Method)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at java.lang.reflect.Method.invoke(Method.java:521)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at dalvik.system.NativeStart.main(Native Method)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): Caused by: java.lang.NullPointerException
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at com.android.Listview.onCreate(Listview.java:40)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-19 16:47:22.221: ERROR/AndroidRuntime(3437): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
please help me.
解决方案
imageview1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, 50));
textview1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, 50));
listview01.setLayoutParams(new
LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
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