java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'int android.view.View.getId（）'
点击动物时，应用程序崩溃。我了解viewById和onClick方法，但不知道该怎么看
这是我从logcat得到的错误：
Process: com.example.ar, PID: 4416
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getId()' on a null object reference
at com.example.ar.MainActivity.setBackground(MainActivity.java:428)
at com.example.ar.MainActivity.onClick(MainActivity.java:381)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
有我的MainActivity代码
ArFragment arFragment;
private ModelRenderable bearRenderable, catRenderable, cowRenderable,
dogRenderable,elephantRenderable,ferretRenderable,hippopotamusRenderable, horseRenderable,koalaRenderable,lionRenderable,reindeerRenderable,wolverineRenderable;
ImageView bear, cat, cow, dog, elephant, ferret, hippopotamus, horse, koala, lion, reindeer, wolverine;
View arrayView[];
int selected = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.sceneform_ux_fragment);
//View
bear = (ImageView) findViewById(R.id.bear);
cat = (ImageView) findViewById(R.id.cat);
dog = (ImageView) findViewById(R.id.dog);
cow = (ImageView) findViewById(R.id.cow);
elephant = (ImageView) findViewById(R.id.elephant);
ferret = (ImageView) findViewById(R.id.ferret);
hippopotamus = (ImageView) findViewById(R.id.hippopotamus);
horse = (ImageView) findViewById(R.id.horse);
koala = (ImageView) findViewById(R.id.lion);
reindeer = (ImageView) findViewById(R.id.reindeer);
wolverine = (ImageView) findViewById(R.id.wolverine);
SetArrayView();
SetClickListener();
setupModel();
arFragment.setOnTapArPlaneListener(new BaseArFragment.OnTapArPlaneListener() {
@Override
public void onTapPlane(HitResult hitResult, Plane plane, MotionEvent motionEvent) {
//kill
if (selected == 1) {
Anchor anchor = hitResult.createAnchor();
AnchorNode anchorNode = new AnchorNode(anchor);
anchorNode.setParent(arFragment.getArSceneView().getScene());
createModel(anchorNode, selected);
}
}
});
}
private void setupModel() {
ModelRenderable.builder()
.setSource(this, R.raw.bear)
.build().thenAccept(renderable -> bearRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load bear model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.cat)
.build().thenAccept(renderable -> catRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load cat model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.cow)
.build().thenAccept(renderable -> cowRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load cow model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.dog)
.build().thenAccept(renderable -> dogRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load dog model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.elephant)
.build().thenAccept(renderable -> elephantRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load elephant model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.ferret)
.build().thenAccept(renderable -> ferretRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load ferret model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.hippopotamus)
.build().thenAccept(renderable -> hippopotamusRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load hippopotamus model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.horse)
.build().thenAccept(renderable -> horseRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load horse model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.koala_bear)
.build().thenAccept(renderable -> koalaRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load koala model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.lion)
.build().thenAccept(renderable -> lionRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load lion model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.reindeer)
.build().thenAccept(renderable -> reindeerRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load reindeer model", Toast.LENGTH_SHORT).show();
return null;
}
);
ModelRenderable.builder()
.setSource(this, R.raw.wolverine)
.build().thenAccept(renderable -> wolverineRenderable = renderable)
.exceptionally(
throwable -> {
Toast.makeText(this, "Unnable to load wolverine model", Toast.LENGTH_SHORT).show();
return null;
}
);
}
private void createModel(AnchorNode anchorNode, int selected) {
if (selected == 1) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(bearRenderable);
bear.select();
addName(anchorNode,bear,"Bear");
}
if (selected == 2) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(catRenderable);
bear.select();
addName(anchorNode,bear,"Cat");
}
if (selected == 3) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(cowRenderable);
bear.select();
addName(anchorNode,bear,"Cow");
}
if (selected == 4) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(dogRenderable);
bear.select();
addName(anchorNode,bear,"Dog");
}
if (selected == 5) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(elephantRenderable);
bear.select();
addName(anchorNode,bear,"Elephant");
}
if (selected == 6) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(ferretRenderable);
bear.select();
addName(anchorNode,bear,"Ferret");
}
if (selected == 7) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(hippopotamusRenderable);
bear.select();
addName(anchorNode,bear,"Hippopotamus");
}
if (selected == 8) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(horseRenderable);
bear.select();
addName(anchorNode,bear,"Horse");
}
if (selected == 9) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(koalaRenderable);
bear.select();
addName(anchorNode,bear,"Koala");
}
if (selected == 10) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(lionRenderable);
bear.select();
addName(anchorNode,bear,"Lion");
}
if (selected == 11) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(reindeerRenderable);
bear.select();
addName(anchorNode,bear,"Reindeer");
}
if (selected == 12) {
TransformableNode bear = new TransformableNode(arFragment.getTransformationSystem());
bear.setParent(anchorNode);
bear.setRenderable(wolverineRenderable);
bear.select();
addName(anchorNode,bear,"Wolverine");
}
}
private void addName(AnchorNode anchorNode, TransformableNode model, String name) {
ViewRenderable.builder().setView(this,R.layout.name_animal)
.build()
.thenAccept(viewRenderable -> {
TransformableNode nameView = new TransformableNode(arFragment.getTransformationSystem());
nameView.setLocalPosition(new Vector3(0f,model.getLocalPosition().y+0.5f,0));
nameView.setParent(anchorNode);
nameView.setRenderable(viewRenderable);
nameView.select();
//text
TextView txt_name = (TextView)viewRenderable.getView();
txt_name.setText(name);
//click to remove animal
txt_name.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
anchorNode.setParent(null);
}
});
});
}
private void SetClickListener() {
for (int i = 0; i < arrayView.length; i++) {
if (arrayView[i] != null)
arrayView[i].setOnClickListener(this);
}
}
private void SetArrayView() {
arrayView = new View[]{ bear,cat,cow,dog,elephant,ferret,hippopotamus,horse,koala,lion,reindeer,wolverine
};
}
@Override
public void onClick(View view) {
if (view.getId()== R.id.bear) {
selected = 1;
setBackground(view.getId());
}
else if (view.getId()==R.id.cat) {
selected = 2;
setBackground(view.getId());
}
else if (view.getId()==R.id.cow) {
selected = 3;
setBackground(view.getId());
}
else if (view.getId()==R.id.dog) {
selected = 4;
setBackground(view.getId());
}
else if (view.getId()==R.id.elephant) {
selected = 5;
setBackground(view.getId());
}
else if (view.getId()==R.id.ferret) {
selected = 6;
setBackground(view.getId());
}
else if (view.getId()==R.id.hippopotamus) {
selected = 7;
setBackground(view.getId());
}
else if (view.getId()==R.id.horse) {
selected =8;
setBackground(view.getId());
}
else if (view.getId()==R.id.koala) {
selected = 9;
setBackground(view.getId());
}
else if (view.getId()==R.id.lion) {
selected = 10;
setBackground(view.getId());
}
else if (view.getId()==R.id.reindeer) {
selected = 11;
setBackground(view.getId());
}
else if (view.getId()==R.id.wolverine) {
selected =12;
setBackground(view.getId());
}
}
private void setBackground(int id) {
for (int i =0;i<arrayView.length;i++){
if (arrayView[i].getId() == id)
arrayView[i].setBackgroundColor(Color.parseColor("#80333639"));
else
arrayView[i].setBackgroundColor(Color.TRANSPARENT);
}
}}
I am new at java programming so help me please to understand where is my mistakes.