EditText

EditTextTextView 的子类,用于进行文字输入等操作,是开发中特别常用的一个控件了,本文主要介绍:

  1. 更改EditText的背景
  2. 设置监听事件
  3. 给EditText设置具有带图片的Hint

监听事件

监听焦点变化

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etInput.setOnFocusChangeListener(new OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
// hasFocus 当前是否获得焦点
}
});

文本输入监听事件

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etInput.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// 文本输入之前回调
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// 输入过程中会频繁回调
}
@Override
public void afterTextChanged(Editable s) {
// 输入结束回调
}
});

自定义EditText背景

如下图所示,当离开当前EditText时,检查输入是否有问题,输入错误会显示红色

定义背景drawable文件

其他形态的背景也相对简单,只有一条线的这种背景drawable写起来还是需要研究一下的,直接上代码啦,主要是用了一个selector -> layer-list -> shape,在select属性改变时,改变线条的颜色。原本是一个矩形,然后将另外三个边偏移一下,只留下底边,达到线条显示的效果。

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<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_selected="true">
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="rectangle">
<solid android:color="@android:color/transparent" />
</shape>
</item>
<item
android:left="-2dip"
android:right="-2dip"
android:top="-2dip">
<shape>
<solid android:color="@android:color/transparent" />
<stroke
android:width="1dip"
android:color="@color/red"
android:dashGap="0dp"
android:dashWidth="0dip" />
</shape>
</item>
</layer-list>
</item>
<item>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape android:shape="rectangle">
<solid android:color="@android:color/transparent" />
</shape>
</item>
<item
android:left="-2dip"
android:right="-2dip"
android:top="-2dip">
<shape>
<solid android:color="@android:color/transparent" />
<stroke
android:width="1dip"
android:color="@color/colorPrimary"
android:dashGap="0dp"
android:dashWidth="0dip" />
</shape>
</item>
</layer-list>
</item>
</selector>

带图片的Hint

如下图所示,实现带有图片的hint,使用 SpannableString实现 ,但是开始的效果不是很理想,图片不能很好的居中,使用重写ImageSpan的方法解决了这个问题

图片垂直居中的span

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class VerticalCenterImageSpan extends ImageSpan {
VerticalCenterImageSpan(Drawable drawable) {
super(drawable);
}
public int getSize(Paint paint, CharSequence text, int start, int end,
Paint.FontMetricsInt fontMetricsInt) {
Drawable drawable = getDrawable();
Rect rect = drawable.getBounds();
if (fontMetricsInt != null) {
Paint.FontMetricsInt fmPaint = paint.getFontMetricsInt();
int fontHeight = fmPaint.bottom - fmPaint.top;// 计算文字的高度
int drHeight = rect.bottom - rect.top;// 计算图片的高度
int top = drHeight / 2 - fontHeight / 4;
int bottom = drHeight / 2 + fontHeight / 4;
fontMetricsInt.ascent = -bottom;
fontMetricsInt.top = -bottom;
fontMetricsInt.bottom = top;
fontMetricsInt.descent = top;
}
return rect.right;
}
@Override
public void draw(Canvas canvas, CharSequence text, int start, int end,
float x, int top, int y, int bottom, Paint paint) {
Drawable drawable = getDrawable();
canvas.save();
int transY;
transY = ((bottom - top) - drawable.getBounds().bottom) / 2 + top;
canvas.translate(x, transY);
drawable.draw(canvas);
canvas.restore();
}
}

设置hint

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// 设置图文hint
private void initEditText(EditText editText) {
SpannableString msp = new SpannableString("图片 写点什么吧...");
Drawable drawable = ContextCompat.getDrawable(getContext(), R.drawable.icon_hint_edit);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
// 这里从start = 0开始,end = 2结束,图片取代了两个字的位置,上面的字符串中国年的图片两个字会被替代
msp.setSpan(new VerticalCenterImageSpan(drawable), 0, 2, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
editText.setHint(msp);
}

修改键盘的回车键

在xml配置

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android:imeOptions="actionSearch"
android:inputType="text"

或在java代码中配置

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editText.setImeOptions(EditorInfo.IME_ACTION_SEARCH);
editText.setInputType(EditorInfo.TYPE_CLASS_TEXT);

实现监听,进行相关操作

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editText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_SEND
|| (event != null && event.getKeyCode() == KeyEvent.KEYCODE_ENTER)) {
//do something;
return true;
}
return false;
}
});
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