Java 动画可绘制-空对象引用
我的动画绘制有问题。它告诉我它指向一个空对象引用,但我很确定它不是。我该如何解决这个问题 在这一点上,任何帮助都会非常有用!谢谢大家!Java 动画可绘制-空对象引用,java,android,android-studio,Java,Android,Android Studio,我的动画绘制有问题。它告诉我它指向一个空对象引用,但我很确定它不是。我该如何解决这个问题 在这一点上,任何帮助都会非常有用!谢谢大家! public class PlayingScreen extends AppCompatActivity implements View.OnClickListener { int notLike_Liked = 1; int Pause_Play = 1; SeekBar seekBar; ImageView back,pause,next,notLikes
public class PlayingScreen extends AppCompatActivity implements View.OnClickListener {
int notLike_Liked = 1;
int Pause_Play = 1;
SeekBar seekBar;
ImageView back,pause,next,notLikes;
TextView text_fixed,text_plus;
ConstraintLayout playing_screen;
AnimationDrawable animationDrawable;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_playing_screen);
playing_screen = findViewById(R.id.playing_screen);
notLikes = findViewById(R.id.notLikes);
text_fixed = findViewById(R.id.text_fixed);
text_plus = findViewById(R.id.text_plus);
seekBar = findViewById(R.id.seekBar);
back = findViewById(R.id.back);
pause = findViewById(R.id.pause);
next = findViewById(R.id.next);
//setting of click listeners ofr buttons
notLikes.setOnClickListener(this);
seekBar.setOnClickListener(this);
back.setOnClickListener(this);
pause.setOnClickListener(this);
next.setOnClickListener(this);
StateListDrawable background = (StateListDrawable) playing_screen.getBackground();
Drawable current = background.getCurrent();
if(current instanceof AnimationDrawable){
animationDrawable =(AnimationDrawable) current;
animationDrawable.setEnterFadeDuration(5000);
animationDrawable.setExitFadeDuration(5000);
animationDrawable.start();
}
}
@Override
protected void onResume() {
super.onResume();
if(animationDrawable != null && animationDrawable.isRunning()){
animationDrawable.start();
}
}
日志类别:
Attempt to invoke virtual method 'android.graphics.drawable.Drawable android.graphics.drawable.StateListDrawable.getCurrent()' on a null object reference at com.musicapp.android.musicapp.PlayingScreen.onCreate(PlayingScreen.java:46) –
XML
我的动画绘制有问题。它告诉我它指向一个空对象引用,但我很确定它不是。我该如何解决这个问题
在这一点上,任何帮助都会非常有用!谢谢大家! 试试下面的代码
public class PlayingScreen extends AppCompatActivity implements View.OnClickListener {
int notLike_Liked = 1;
int Pause_Play = 1;
SeekBar seekBar;
ImageView back,pause,next,notLikes;
TextView text_fixed,text_plus;
ConstraintLayout playing_screen;
AnimationDrawable animationDrawable;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_playing_screen);
playing_screen = findViewById(R.id.playing_screen);
notLikes = findViewById(R.id.notLikes);
text_fixed = findViewById(R.id.text_fixed);
text_plus = findViewById(R.id.text_plus);
seekBar = findViewById(R.id.seekBar);
back = findViewById(R.id.back);
pause = findViewById(R.id.pause);
next = findViewById(R.id.next);
//setting of click listeners ofr buttons
notLikes.setOnClickListener(this);
seekBar.setOnClickListener(this);
back.setOnClickListener(this);
pause.setOnClickListener(this);
next.setOnClickListener(this);
StateListDrawable background = (StateListDrawable) playing_screen.getBackground();
Drawable current = background.getCurrent();
if(current instanceof AnimationDrawable){
animationDrawable =(AnimationDrawable) current;
animationDrawable.setEnterFadeDuration(5000);
animationDrawable.setExitFadeDuration(5000);
animationDrawable.start();
}
}
@Override
protected void onResume() {
super.onResume();
if(animationDrawable != null && animationDrawable.isRunning()){
animationDrawable.start();
}
}
Drawable current=playing_screen.getBackground();
if (current instanceof AnimationDrawable) {
animationDrawable=current;
animationDrawable.setEnterFadeDuration(4000);
animationDrawable.setExitFadeDuration(4000);
animationDrawable.start();
}
}
. Drawable current=background.getCurrent();非常感谢。这很有帮助。但现在我发现了这个错误:尝试调用虚拟方法“android.graphics.drawable.drawable android.graphics.drawable.StateListDrawable.getCurrent()'在com.musicapp.android.musicapp.PlayingScreen.onCreate(PlayingScreen.java:46)上的空对象引用上,编辑回滚以恢复问题的相关代码,因为问题文本不再匹配错误消息谢谢!这很有帮助。但现在我发现了这个错误:尝试调用虚拟方法“android.graphics.drawable.drawable android.graphics.drawable.StateListDrawable.getCurrent()在com.musicapp.android.musicapp.PlayingScreen.onCreate(PlayingScreen.java:46)上的空对象引用上,您可以添加xml吗?这不会让meI添加少量xml。我正在尝试更改Constrail布局的背景色(它的id正在播放屏幕)