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：

@H_404_13@public @H_404_13@class ClearableEditText @H_404_13@extends EditText @H_404_13@implements View.OnTouchListener,View.OnFocusChangeListener,TextWatcher {

    @H_404_13@public @H_404_13@interface Listener {
        @H_404_13@void didClearText();
    }

    @H_404_13@public @H_404_13@void setListener(Listener listener) {
        @H_404_13@this.listener = listener;
    }

    @H_404_13@private Drawable xD;
    @H_404_13@private Listener listener;

    @H_404_13@public ClearableEditText(Context context) {
        @H_404_13@super(context);
        init();
    }

    @H_404_13@public ClearableEditText(Context context,AttributeSet attrs) {
        @H_404_13@super(context,attrs);
        init();
    }

    @H_404_13@public ClearableEditText(Context context,AttributeSet attrs,@H_404_13@int defStyle) {
        @H_404_13@super(context,attrs,defStyle);
        init();
    }

    @Override
    @H_404_13@public @H_404_13@void setOnTouchListener(OnTouchListener l) {
        @H_404_13@this.l = l;
    }

    @Override
    @H_404_13@public @H_404_13@void setOnFocusChangeListener(OnFocusChangeListener f) {
        @H_404_13@this.f = f;
    }

    @H_404_13@private OnTouchListener l;
    @H_404_13@private OnFocusChangeListener f;

    @Override
    @H_404_13@public @H_404_13@boolean onTouch(View v,MotionEvent event) {
        @H_404_13@if (getCompoundDrawables()[2] != @H_404_13@null) {
            @H_404_13@boolean tappedX = event.getX() > (getWidth() - getPaddingRight() - xD
                    .getIntrinsicWidth());
            @H_404_13@if (tappedX) {
                @H_404_13@if (event.getAction() == MotionEvent.ACTION_UP) {
                    setText("");
                    @H_404_13@if (listener != @H_404_13@null) {
                        listener.didClearText();
                    }
                }
                @H_404_13@return @H_404_13@true;
            }
        }
        @H_404_13@if (l != @H_404_13@null) {
            @H_404_13@return l.onTouch(v,event);
        }
        @H_404_13@return @H_404_13@false;
    }

    @Override
    @H_404_13@public @H_404_13@void onFocusChange(View v,@H_404_13@boolean hasFocus) {
        @H_404_13@if (hasFocus) {
            setClearIconVisible(getText().length() > 0);
        } @H_404_13@else {
            setClearIconVisible(@H_404_13@false);
        }
        @H_404_13@if (f != @H_404_13@null) {
            f.onFocusChange(v,hasFocus);
        }
    }

    @Override
    @H_404_13@public @H_404_13@void onTextChanged(CharSequence s,@H_404_13@int start,@H_404_13@int before,@H_404_13@int count) {
        @H_404_13@if (isFocused()) {
            setClearIconVisible(getText().length() > 0);
        }
    }

    @Override
    @H_404_13@public @H_404_13@void beforeTextChanged(CharSequence s,@H_404_13@int count,@H_404_13@int after) {

    }

    @Override
    @H_404_13@public @H_404_13@void afterTextChanged(Editable s) {

    }

    @H_404_13@private @H_404_13@void init() {
        xD = getCompoundDrawables()[2];
        @H_404_13@if (xD == @H_404_13@null) {
            xD = getResources()
                    .getDrawable(android.R.drawable.presence_offline);
        }
        xD.setBounds(0,0,xD.getIntrinsicWidth(),xD.getIntrinsicHeight());
        setClearIconVisible(@H_404_13@false);
        @H_404_13@super.setOnTouchListener(@H_404_13@this);
        @H_404_13@super.setOnFocusChangeListener(@H_404_13@this);
        addTextChangedListener(@H_404_13@this);
    }

    @H_404_13@protected @H_404_13@void setClearIconVisible(@H_404_13@boolean visible) {
        @H_404_13@boolean wasVisible = (getCompoundDrawables()[2] != @H_404_13@null);
        @H_404_13@if (visible != wasVisible) {
            Drawable x = visible ? xD : @H_404_13@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！