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我想在应用启动时隐藏所有图像 ImageButton；

我怎样才能存档呢？这是代码：

ImageButton imgBtn[];

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

private void hideBtn(){
        for (int i = 0; i < 3; i++) {
            imgBtn[i] = (ImageButton) findViewById("R.id.myBTN"+[i]);
            imgBtn[i].setVisibility(View.GONE);
        }
}

更新 我改变了 hideBtn 方法然后我在测试时强制关闭

 -159   private void hideBtn(){
 -160       for (int i = 0; i < 3; i++) {
 -161           int id = getResources().getIdentifier("myBTN"+i,"id", "com.my.app");
 -162           imgBtn[i] = (ImageButton)findViewById(id);
 -163           imgBtn[i].setVisibility(View.GONE);
 -164       }
 -165   }

崩溃日志猫报告：

03-18 16:46:05.125: E/AndroidRuntime(19463):    at dalvik.system.NativeStart.main(Native Method)
03-18 16:46:05.125: E/AndroidRuntime(19463): Caused by: java.lang.NullPointerException
03-18 16:46:05.125: E/AndroidRuntime(19463):    at com.my.app.Main.hideBtn(Main.java:162)
03-18 16:46:05.125: E/AndroidRuntime(19463):    at com.my.app.Main.onCreate(Main.java:61)
03-18 16:46:05.125: E/AndroidRuntime(19463):    at android.app.Activity.performCreate(Activity.java:5108)
03-18 16:46:05.125: E/AndroidRuntime(19463):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-18 16:46:05.125: E/AndroidRuntime(19463):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2266)
03-18 16:46:05.125: E/AndroidRuntime(19463):    ... 11 more

更新：这是 xml 代码：

<ImageButton
        android:id="@+id/myBTN1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:background="@drawable/button" />

<ImageButton
        android:id="@+id/myBTN2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/myBTN1"
        android:layout_below="@+id/myBTN1"
        android:layout_marginTop="12dp"
        android:background="@drawable/button" />

<ImageButton
        android:id="@+id/myBTN3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/myBTN2"
        android:layout_below="@+id/myBTN2"
        android:layout_marginTop="12dp"
        android:background="@drawable/button" />
4

1 回答 1

1

findViewById needs the argument of type int but you are passing type of string. You need to get the resource id first.

you can use getIdentifier method of resource class to get the id, check this getIdentifier

do like this

int id=getResources().getIdentifier("myBTN"+[i], "id", "com.mypackage.myapp");

then 

imgBtn[i] = (ImageButton) findViewById(id);
于 2013-03-17T14:39:55.740 回答