getCompoundDrawables

getCompoundDrawables

方法简介：

用于获取当下该控件的上下左右位置的Drawable引用，该方法返回的是Drawable[]数组，length为4，分别对应Left，Top，Right和Bottom的Drawable引用。比如：以下代码的Edittext，drawable[2]就对应于EditText控件的右端。在代码中动态添加图标就用到这个方法，相当于XML文件中的drawableRight。



代码：

public class ClearableEditText extends EditText implements View.OnTouchListener,
View.OnFocusChangeListener, TextWatcher {

public interface Listener {
void didClearText();
}

public void setListener(Listener listener) {
this.listener = listener;
}

private Drawable xD;
private Listener listener;

public ClearableEditText(Context context) {
super(context);
init();
}

public ClearableEditText(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

public ClearableEditText(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}

@Override
public void setOnTouchListener(OnTouchListener l) {
this.l = l;
}

@Override
public void setOnFocusChangeListener(OnFocusChangeListener f) {
this.f = f;
}

private OnTouchListener l;
private OnFocusChangeListener f;

@Override
public boolean onTouch(View v, MotionEvent event) {
if (getCompoundDrawables()[2] != null) {
boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - xD
.getIntrinsicWidth());
if (tappedX) {
if (event.getAction() == MotionEvent.ACTION_UP) {
setText("");
if (listener != null) {
listener.didClearText();
}
}
return true;
}
}
if (l != null) {
return l.onTouch(v, event);
}
return false;
}

@Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus) {
setClearIconVisible(getText().length() > 0);
} else {
setClearIconVisible(false);
}
if (f != null) {
f.onFocusChange(v, hasFocus);
}
}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (isFocused()) {
setClearIconVisible(getText().length() > 0);
}
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {

}

@Override
public void afterTextChanged(Editable s) {

}

private void init() {
xD = getCompoundDrawables()[2];
if (xD == null) {
xD = getResources()
.getDrawable(android.R.drawable.presence_offline);
}
xD.setBounds(0, 0, xD.getIntrinsicWidth(), xD.getIntrinsicHeight());
setClearIconVisible(false);
super.setOnTouchListener(this);
super.setOnFocusChangeListener(this);
addTextChangedListener(this);
}

protected void setClearIconVisible(boolean visible) {
boolean wasVisible = (getCompoundDrawables()[2] != null);
if (visible != wasVisible) {
Drawable x = visible ? xD : null;
setCompoundDrawables(getCompoundDrawables()[0],
getCompoundDrawables()[1], x, getCompoundDrawables()[3]);
}
}

}

拓展：

登录界面经常用到密码的显示和隐藏按钮，实现如下代码：

loginPswEt.setTransformationMethod(HideReturnsTransformationMethod.getInstance());//隐藏密码
loginPswEt.setTransformationMethod(PasswordTransformationMethod.getInstance());//显示密码

此至！