我创建了一个包含 3 个RelativeLayout
包含的布局。其中 2 个是不可见的,当我按下一个按钮时,我想让它们可见并显示在顶部。可能吗?
我怎样才能制作安卓:
layout_below="@id/pag6a_1"
以编程方式?
这让我犯了一个错误!这是我的代码:`protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); 设置内容视图(R.layout.pag6a);
RelativeLayout pag6a_2 = (RelativeLayout) findViewById(R.id.pag6a_2);
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) pag6a_2.getLayoutParams();
pag6a_2.setVisibility(View.VISIBLE);
params.addRule(RelativeLayout.BELOW, R.id.pag6a_3);`
..这是我的日志:
10-10 21:27:11.025:E/AndroidRuntime(3117):致命异常:主要 10-10 21:27:11.025:E/AndroidRuntime(3117):java.lang.RuntimeException:无法启动活动 ComponentInfo{com. beandroid.pirani/com.beandroid.pirani.Pag6A}:java.lang.ClassCastException:android.widget.LinearLayout$LayoutParams 无法转换为 android.widget.RelativeLayout$LayoutParams 10-10 21:27:11.025:E/AndroidRuntime( 3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 10 -10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.access$600(ActivityThread.java:141) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android. app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.os.Handler.dispatchMessage(Handler.java:99) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在android.os.Looper.loop(Looper.java:137) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.main(ActivityThread.java:5041) 10-10 21: 27:11.025: E/AndroidRuntime(3117): 在 java.lang.reflect.Method.invokeNative(Native Method) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 java.lang.reflect.Method。调用(Method.java:511)10-10 21:27:11.025:E/AndroidRuntime(3117):在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)10-10 21: 27:11.025: E/AndroidRuntime(3117): 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 dalvik.system .NativeStart。main(Native Method) 10-10 21:27:11.025: E/AndroidRuntime(3117): Caused by: java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams 无法转换为 android.widget.RelativeLayout$LayoutParams 10- 10 21:27:11.025: E/AndroidRuntime(3117): 在 com.beandroid.pirani.Pag6A.onCreate(Pag6A.java:44) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android。 app.Activity.performCreate(Activity.java:5104) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 10-10 21:27: 11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 10-10 21:27:11.025: E/AndroidRuntime(3117): ... 11 更多LinearLayout$LayoutParams 无法转换为 android.widget.RelativeLayout$LayoutParams 10-10 21:27:11.025: E/AndroidRuntime(3117): at com.beandroid.pirani.Pag6A.onCreate(Pag6A.java:44) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Activity.performCreate(Activity.java:5104) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Instrumentation .callActivityOnCreate(Instrumentation.java:1080) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 10-10 21:27:11.025: E /AndroidRuntime(3117): ... 11 更多LinearLayout$LayoutParams 无法转换为 android.widget.RelativeLayout$LayoutParams 10-10 21:27:11.025: E/AndroidRuntime(3117): at com.beandroid.pirani.Pag6A.onCreate(Pag6A.java:44) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Activity.performCreate(Activity.java:5104) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Instrumentation .callActivityOnCreate(Instrumentation.java:1080) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 10-10 21:27:11.025: E /AndroidRuntime(3117): ... 11 更多app.Activity.performCreate(Activity.java:5104) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 10-10 21:27: 11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 10-10 21:27:11.025: E/AndroidRuntime(3117): ... 11 更多app.Activity.performCreate(Activity.java:5104) 10-10 21:27:11.025: E/AndroidRuntime(3117): 在 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 10-10 21:27: 11.025: E/AndroidRuntime(3117): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 10-10 21:27:11.025: E/AndroidRuntime(3117): ... 11 更多