当我尝试去动画所在的活动时，它总是崩溃。我的日志猫在这里，我的其他文件都在这里。
我试图通过DrawableAnimation创建动画，但我不知道为什么在设置背景资源时出现错误
02-03 18:52:30.323 4831-4831/com.secsys.gagacamaso.gagacamaso E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.secsys.gagacamaso.gagacamaso, PID: 4831
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.secsys.gagacamaso.gagacamaso/com.secsys.gagacamaso.gagacamaso.Menu}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setBackgroundResource(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setBackgroundResource(int)' on a null object reference
at com.secsys.gagacamaso.gagacamaso.Menu.onCreate(Menu.java:31)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
public class Menu extends Activity {
ImageButton enable;
ImageView rm1;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
setViews();
enable = (ImageButton)findViewById(R.id.enable);
lock();
rm1.setBackgroundResource(R.drawable.rm_animation);
}
public void setViews(){
ImageView rm1 = (ImageView)findViewById(R.id.rm1);
}
private void lock(){
enable.setTag(1);
enable.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final int state =(Integer) v.getTag();
if(state == 1) {
Toast.makeText(Menu.this, "ENABLED!", Toast.LENGTH_SHORT).show();
enable.setBackgroundResource(R.drawable.disable);
AnimationDrawable rmanim = (AnimationDrawable) rm1.getBackground();
rmanim.start();
v.setTag(0);
} else {
Toast.makeText(Menu.this, "DISABLED!", Toast.LENGTH_SHORT).show();
enable.setBackgroundResource(R.drawable.enable);
v.setTag(1); //pause
}
}
});
}
<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
android:oneshot="true">
<item android:drawable="@drawable/rm1" android:duration="150"/>
<item android:drawable="@drawable/rm1glow1" android:duration="150"/>
<item android:drawable="@drawable/rm1glow2" android:duration="150"/>
<item android:drawable="@drawable/rm1glow3" android:duration="150"/>
</animation-list>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<GridLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="100dp"
android:layout_centerHorizontal="true"
android:id="@+id/gridLayout2">
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/rm1"
android:layout_row="0"
android:layout_column="0"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/rm4"
android:layout_row="0"
android:layout_column="2"
android:background="@drawable/rm1"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/rm2"
android:layout_row="1"
android:layout_column="0"
android:background="@drawable/rm1"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/rm5"
android:layout_row="1"
android:layout_column="2"
android:background="@drawable/rm1"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/rm3"
android:layout_row="2"
android:layout_column="0"
android:background="@drawable/rm1"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/lrm1"
android:layout_row="0"
android:layout_column="1"
android:layout_gravity="fill_vertical"
android:layout_rowSpan="3"
android:background="@drawable/rm2"/>
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:id="@+id/lrm2"
android:layout_row="2"
android:layout_column="2"
android:background="@drawable/rm2a"/>
</GridLayout>
<ImageButton
android:layout_width="200dp"
android:layout_height="50dp"
android:id="@+id/enable"
android:layout_below="@+id/gridLayout2"
android:layout_centerHorizontal="true"
android:background="@drawable/enable"/>
</RelativeLayout>
答案 0 :(得分：0)
boss这个空指针异常是因为
public void setViews(){
ImageView rm1 = (ImageView)findViewById(R.id.rm1);
}
在这种情况下，用于设置背景的rm1的引用将始终为null。
尝试做
public void setViews(){
rm1 = (ImageView)findViewById(R.id.rm1);
}
答案 1 :(得分：0)
从setViews（）方法中删除ImageView，因为它会创建一个局部变量并初始化它而不是顶级rm1。
public void setViews(){
rm1 = (ImageView)findViewById(R.id.rm1);
}
答案 2 :(得分：0)
您应首先从可绘制的xml文件创建动画，然后将其调用到ImageView。
Animation animation = AnimationUtils.loadAnimation(this, R.anim.rm_animation);
imageView.startAnimation(animation);
只需创建一个新的动画文件夹并创建新的动画文件，然后从您在drawable文件夹中的rm_animation.xml中复制所有内容。
从setView() ImageView中删除。如果您已经在方法之外初始化变量，那么您应该只有imageView = (ImageView) findViewById(R.id.imageView);。