Java 如何在Android中获取ImageView大小?
我正在尝试获取imageview大小,但它返回零。我知道这是因为我在onCreate()中调用了它。有人能帮我怎么做吗?这样,当我点击一个按钮时,它会显示该图像视图的大小。这里是我迄今为止所尝试的Java 如何在Android中获取ImageView大小?,java,android,Java,Android,我正在尝试获取imageview大小,但它返回零。我知道这是因为我在onCreate()中调用了它。有人能帮我怎么做吗?这样,当我点击一个按钮时,它会显示该图像视图的大小。这里是我迄今为止所尝试的 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button)findViewById(R.id.btn);
imgView = (ImageView)findViewById(R.id.imgView);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
getSize();
}
});
}
void getSize)
{
BitmapDrawable bd = (BitmapDrawable)imgView.getDrawable();
bmp = bd.getBitmap();
Bitmap op = Bitmap.createBitmap(bmp, imgWidth/2, imgHeight/2, imgWidth, imgHeight);
imgView.setImageBitmap(op);
}
@Override
public void onWindowFocusChanged(boolean hasFocus){
imgWidth=imgView.getWidth();
imgHeight=imgView.getHeight();
}
更新
这就是我现在得到的
06-18 00:13:20.206: E/AndroidRuntime(919): FATAL EXCEPTION: main
06-18 00:13:20.206: E/AndroidRuntime(919): java.lang.IllegalArgumentException: x must be >= 0
06-18 00:13:20.206: E/AndroidRuntime(919): at android.graphics.Bitmap.checkXYSign(Bitmap.java:225)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.graphics.Bitmap.createBitmap(Bitmap.java:495)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.graphics.Bitmap.createBitmap(Bitmap.java:471)
06-18 00:13:20.206: E/AndroidRuntime(919): at com.example.bitmapfun.Main.Gray(Main.java:44)
06-18 00:13:20.206: E/AndroidRuntime(919): at com.example.bitmapfun.Main$1.onClick(Main.java:34)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.view.View.performClick(View.java:3527)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.view.View$PerformClick.run(View.java:14234)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.os.Handler.handleCallback(Handler.java:605)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.os.Handler.dispatchMessage(Handler.java:92)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.os.Looper.loop(Looper.java:137)
06-18 00:13:20.206: E/AndroidRuntime(919): at android.app.ActivityThread.main(ActivityThread.java:4441)
06-18 00:13:20.206: E/AndroidRuntime(919): at java.lang.reflect.Method.invokeNative(Native Method)
06-18 00:13:20.206: E/AndroidRuntime(919): at java.lang.reflect.Method.invoke(Method.java:511)
06-18 00:13:20.206: E/AndroidRuntime(919): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-18 00:13:20.206: E/AndroidRuntime(919): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-18 00:13:20.206: E/AndroidRuntime(919): at dalvik.system.NativeStart.main(Native Method)
试试看,它使用视图树观察者来获取宽度和高度。以前的方法不起作用,因为视图没有在屏幕中绘制(布局过程不完整)。类似的方法也应该奏效:
final ImageView iv = (ImageView)findViewById(R.id.image);
ViewTreeObserver vto = iv.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
Log.d("width",""+iv.getWidth());
}
});
只有将组件添加到父窗口,然后将窗口“打包”或布局到正确的大小,才能设置大小。因此在
onCreate
中,它将是0,0
当函数被调用时,你就不能得到它的大小吗
void getSize()
{
imgWidth=imgView.getWidth();
imgHeight=imgView.getHeight();
BitmapDrawable bd = (BitmapDrawable)imgView.getDrawable();
bmp = bd.getBitmap();
Bitmap op = Bitmap.createBitmap(bmp, imgWidth/2, imgHeight/2, imgWidth, imgHeight);
imgView.setImageBitmap(op);
}
可能尝试使用
imgView.getLayoutParamas().width
和imgView.getLayoutParamas().height
而不是getWidth()
和getHeight()
。ViewTreeObserver()是go@G.T.getLayoutParams()不适用于我。。给出相同的错误。@IllegalArgument您能告诉我或告诉我如何在按钮onclick方法中使用ViewTreeObserver()的代码吗谢谢。您确定调用了onWindowFocusChange()
方法吗?你能用调试器检查一下吗?为什么要在函数getSize()中设置位图?这是个好问题!我只是叫它getSize
OP就是这么叫的。虽然在他的堆栈跟踪中,它似乎被称为Gray
。。。