注：本文转载自csdn，其中实现清除功能所采用的方案比较可取。
原文如下：
项目要求：做出包含根据情况可变色的下划线，左侧有可变图标，右侧有可变删除标志的edittext,如图
记录制作过程：
第一版本：
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public class LineEditText extends EditText { private Paint mPaint; private int color; public static final int STATUS_FOCUSED = 1; public static final int STATUS_UNFOCUSED = 2; public static final int STATUS_ERROR = 3; private int status = 2; private Drawable del_btn; private Drawable del_btn_down; private int focusedDrawableId = R.drawable.user_select;// 默认的 private int unfocusedDrawableId = R.drawable.user; private int errorDrawableId = R.drawable.user_error; Drawable left = null; private Context mContext; public LineEditText(Context context) { super(context); mContext = context; init(); } public LineEditText(Context context, AttributeSet attrs) { super(context, attrs); mContext = context; init(); } public LineEditText(Context context, AttributeSet attrs, int defStryle) { super(context, attrs, defStryle); mContext = context; TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.lineEdittext, defStryle, 0); focusedDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableFocus, R.drawable.user_select); unfocusedDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableUnFocus, R.drawable.user); errorDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableError, R.drawable.user_error); a.recycle(); init(); } /** * 2014/7/31 * * @author Aimee.ZHANG */ private void init() { mPaint = new Paint(); // mPaint.setStyle(Paint.Style.FILL); mPaint.setStrokeWidth(3.0f); color = Color.parseColor("#bfbfbf"); setStatus(status); del_btn = mContext.getResources().getDrawable(R.drawable.del_but_bg); del_btn_down = mContext.getResources().getDrawable(R.drawable.del_but_bg_down); addTextChangedListener(new TextWatcher() { @Override public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) { } @Override public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) { } @Override public void afterTextChanged(Editable arg0) { setDrawable(); } }); setDrawable(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mPaint.setColor(color); canvas.drawLine(0, this.getHeight() - 1, this.getWidth(), this.getHeight() - 1, mPaint); } // 删除图片 private void setDrawable() { if (length() < 1) { setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn, null); } else { setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn_down,null); } } // 处理删除事件 @Override public boolean onTouchEvent(MotionEvent event) { if (del_btn_down != null && event.getAction() == MotionEvent.ACTION_UP) { int eventX = (int) event.getRawX(); int eventY = (int) event.getRawY(); Log.e("eventXY", "eventX = " + eventX + "; eventY = " + eventY); Rect rect = new Rect(); getGlobalVisibleRect(rect); rect.left = rect.right - 50; if (rect.contains(eventX, eventY)) setText(""); } return super.onTouchEvent(event); } public void setStatus(int status) { this.status = status; if (status == STATUS_ERROR) { try { left = getResources().getDrawable(errorDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#f57272")); } else if (status == STATUS_FOCUSED) { try { left = getResources().getDrawable(focusedDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#5e99f3")); } else { try { left = getResources().getDrawable(unfocusedDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#bfbfbf")); } if (left != null) {// left.setBounds(0, 0, 30, 40);// this.setCompoundDrawables(left, null, null, null); setCompoundDrawablesWithIntrinsicBounds(left,null,del_btn,null); } postInvalidate(); } public void setLeftDrawable(int focusedDrawableId, int unfocusedDrawableId, int errorDrawableId) { this.focusedDrawableId = focusedDrawableId; this.unfocusedDrawableId = unfocusedDrawableId; this.errorDrawableId = errorDrawableId; setStatus(status); } @Override protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) { super.onFocusChanged(focused, direction, previouslyFocusedRect); if (focused) { setStatus(STATUS_FOCUSED); } else { setStatus(STATUS_UNFOCUSED); } } @Override protected void finalize() throws Throwable { super.finalize(); }; public void setColor(int color) { this.color = color; this.setTextColor(color); invalidate(); }} |
效果图：
代码解释：
变量名 STATUS_FOCUSED,STATUS_UNFOCUSED,STATUS_ERROR 标示了三种状态，选中状况为蓝色，未选中状态为灰色，错误状态为红色。focusedDrawableId unfocusedDrawableId errorDrawableId 存放三种状态的图片，放置于最左侧。
canvas.drawLine(0, this.getHeight() - 1, this.getWidth(),this.getHeight() - 1, mPaint); //画editText最下方的线
setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn, null); //放置左边的和右边的图片（左，上，右，下）
相当于 android:drawableLeft="" android:drawableRight=""
onTouchEvent 当手机点击时，第一个先走的函数，当点击右侧删除图标是清空edittext
setStatus 更具不同的状态，左边的图片不一样
存在的问题：
这版本虽然基本功能已经实现，但是不符合需求，设计中要求文本框中无文字时，右侧删除按钮不显示，不点击删除按钮，删除按钮要保持灰色，点击时才可以变蓝色。因此有了第二个版本
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public class LineEditText extends EditText implements TextWatcher,OnFocusChangeListener{ private Paint mPaint; private int color; public static final int STATUS_FOCUSED = 1; public static final int STATUS_UNFOCUSED = 2; public static final int STATUS_ERROR = 3; private int status = 2; private Drawable del_btn; private Drawable del_btn_down; private int focusedDrawableId = R.drawable.user_select;// 默认的 private int unfocusedDrawableId = R.drawable.user; private int errorDrawableId = R.drawable.user_error; Drawable left = null; private Context mContext; /** * 是否获取焦点，默认没有焦点 */ private boolean hasFocus = false; /** * 手指抬起时的X坐标 */ private int xUp = 0; public LineEditText(Context context) { super(context); mContext = context; init(); } public LineEditText(Context context, AttributeSet attrs) { super(context, attrs); mContext = context; init(); } public LineEditText(Context context, AttributeSet attrs, int defStryle) { super(context, attrs, defStryle); mContext = context; TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.lineEdittext, defStryle, 0); focusedDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableFocus, R.drawable.user_select); unfocusedDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableUnFocus, R.drawable.user); errorDrawableId = a.getResourceId( R.styleable.lineEdittext_drawableError, R.drawable.user_error); a.recycle(); init(); } /** * 2014/7/31 * * @author Aimee.ZHANG */ private void init() { mPaint = new Paint(); // mPaint.setStyle(Paint.Style.FILL); mPaint.setStrokeWidth(3.0f); color = Color.parseColor("#bfbfbf"); setStatus(status); del_btn = mContext.getResources().getDrawable(R.drawable.del_but_bg); del_btn_down = mContext.getResources().getDrawable(R.drawable.del_but_bg_down); addListeners(); setCompoundDrawablesWithIntrinsicBounds(left, null, null, null); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mPaint.setColor(color); canvas.drawLine(0, this.getHeight() - 1, this.getWidth(), this.getHeight() - 1, mPaint); } // 删除图片// private void setDrawable() {// if (length() < 1) {// setCompoundDrawablesWithIntrinsicBounds(left, null, null, null);// } else {// setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn,null);// }// } // 处理删除事件 @Override public boolean onTouchEvent(MotionEvent event) { if (del_btn != null && event.getAction() == MotionEvent.ACTION_UP) { // 获取点击时手指抬起的X坐标 xUp = (int) event.getX(); Log.e("xUp", xUp+""); /*Rect rect = new Rect(); getGlobalVisibleRect(rect); rect.left = rect.right - 50;*/ // 当点击的坐标到当前输入框右侧的距离小于等于getCompoundPaddingRight()的距离时，则认为是点击了删除图标 if ((getWidth() - xUp) <= getCompoundPaddingRight()) { if (!TextUtils.isEmpty(getText().toString())) { setText(""); } } }else if(del_btn != null && event.getAction() == MotionEvent.ACTION_DOWN && getText().length()!=0){ setCompoundDrawablesWithIntrinsicBounds(left,null,del_btn_down,null); }else if(getText().length()!=0){ setCompoundDrawablesWithIntrinsicBounds(left,null,del_btn,null); } return super.onTouchEvent(event); } public void setStatus(int status) { this.status = status; if (status == STATUS_ERROR) { try { left = getResources().getDrawable(errorDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#f57272")); } else if (status == STATUS_FOCUSED) { try { left = getResources().getDrawable(focusedDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#5e99f3")); } else { try { left = getResources().getDrawable(unfocusedDrawableId); } catch (NotFoundException e) { e.printStackTrace(); } setColor(Color.parseColor("#bfbfbf")); } if (left != null) {// left.setBounds(0, 0, 30, 40);// this.setCompoundDrawables(left, null, null, null); setCompoundDrawablesWithIntrinsicBounds(left,null,null,null); } postInvalidate(); } public void setLeftDrawable(int focusedDrawableId, int unfocusedDrawableId, int errorDrawableId) { this.focusedDrawableId = focusedDrawableId; this.unfocusedDrawableId = unfocusedDrawableId; this.errorDrawableId = errorDrawableId; setStatus(status); } private void addListeners() { try { setOnFocusChangeListener(this); addTextChangedListener(this); } catch (Exception e) { e.printStackTrace(); } } @Override protected void onFocusChanged(boolean focused, int direction, Rect previouslyFocusedRect) { super.onFocusChanged(focused, direction, previouslyFocusedRect); this.hasFocus=focused; if (focused) { setStatus(STATUS_FOCUSED); } else { setStatus(STATUS_UNFOCUSED); setCompoundDrawablesWithIntrinsicBounds(left,null,null,null); } } @Override protected void finalize() throws Throwable { super.finalize(); }; public void setColor(int color) { this.color = color; this.setTextColor(color); invalidate(); } @Override public void afterTextChanged(Editable arg0) { // TODO Auto-generated method stub postInvalidate(); } @Override public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) { // TODO Auto-generated method stub if (TextUtils.isEmpty(arg0)) { // 如果为空，则不显示删除图标 setCompoundDrawablesWithIntrinsicBounds(left, null, null, null); } else { // 如果非空，则要显示删除图标 setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn, null); } } @Override public void onTextChanged(CharSequence s, int start, int before, int after) { if (hasFocus) { if (TextUtils.isEmpty(s)) { // 如果为空，则不显示删除图标 setCompoundDrawablesWithIntrinsicBounds(left, null, null, null); } else { // 如果非空，则要显示删除图标 setCompoundDrawablesWithIntrinsicBounds(left, null, del_btn, null); } } } @Override public void onFocusChange(View arg0, boolean arg1) { // TODO Auto-generated method stub try { this.hasFocus = arg1; } catch (Exception e) { e.printStackTrace(); } }} |
效果图：
比较关键的方法是：onTouchEvent
当进入界面，点击输入框，要判断输入框中是否已有文字，如果有则显示灰色的删除按钮，如果没有则不显示，如果点击了删除按钮，删除按钮变蓝色
存在的问题：
这个版本依旧存在问题，就是输入长度超过输入框，所画的线不会延伸，如图
解决办法：
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@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mPaint.setColor(color); int x=this.getScrollX(); int w=this.getMeasuredWidth(); canvas.drawLine(0, this.getHeight() - 1, w+x, this.getHeight() - 1, mPaint); } |
w：获取控件长度
X：延伸后的长度
最终效果：
