方法一:代码实现
1. 自定义状态效果可以通过代码实现,也可以通过xml定义style实现。
2. 下面先介绍代码实现,通过StateListDrawable定义Button背景。
3. 由于View类中PRESSED_ENABLED_STATE_SET值不是公共常量,所以通过继承来访问了。
特注:其他控件的效果,比如ImageView,也可以通过这种方法实现,但是由于ImageView默认是没焦点,不可点击的,需要自己更改(需要点击就设置android:clickable="true" , 需要能够选中就设置android:focusable="true" )。
java 代码:
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package
com.test.TestButton;
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import
android.app.Activity;
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import
android.content.Context;
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import
android.graphics.drawable.Drawable;
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import
android.graphics.drawable.StateListDrawable;
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import
android.os.Bundle;
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import
android.view.View;
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import
android.widget.Button;
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public
class TestButton extends Activity {
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public void
onCreate(Bundle savedInstanceState) { |
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super .onCreate(savedInstanceState); |
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setContentView(R.layout.main); |
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Integer[] mButtonState = { R.drawable.defaultbutton, |
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R.drawable.focusedpressed, R.drawable.pressed }; |
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Button mButton = (Button) findViewById(R.id.button); |
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MyButton myButton = new
MyButton( this ); |
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mButton.setBackgroundDrawable(myButton.setbg(mButtonState)); |
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class MyButton
extends View {
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public MyButton(Context context) {
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public StateListDrawable setbg(Integer[] mImageIds) {
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StateListDrawable bg = new
StateListDrawable(); |
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Drawable normal = this .getResources().getDrawable(mImageIds[ 0 ]); |
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Drawable selected = this .getResources().getDrawable(mImageIds[ 1 ]); |
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Drawable pressed = this .getResources().getDrawable(mImageIds[ 2 ]); |
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bg.addState(View.PRESSED_ENABLED_STATE_SET, pressed); |
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bg.addState(View.ENABLED_FOCUSED_STATE_SET, selected); |
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bg.addState(View.ENABLED_STATE_SET, normal); |
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bg.addState(View.FOCUSED_STATE_SET, selected); |
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bg.addState(View.EMPTY_STATE_SET, normal); |
XML代码:
在res/drawable下面新建mybutton_background.xml文件,内容如下:
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<? xml version=”1.0″ encoding=”utf-8″?>
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< selector xmlns:android=”http://schemas.android.com/apk/res/android“> |
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< item android:state_focused=”true”
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android:state_pressed=”false” |
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android:drawable=”@drawable/yellow” /> |
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< item android:state_focused=”true”
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android:state_pressed=”true” |
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android:drawable=”@drawable/green” /> |
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< item android:state_focused=”false”
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android:state_pressed=”true” |
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android:drawable=”@drawable/blue” /> |
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< item android:drawable=”@drawable/grey” />
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这里面就定义了在不同状态下的显示图片,然后在layout里面定义Button的时候,指定它的background为这个mybutton_background
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<? xml version=”1.0″ encoding=”utf-8″?>
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< LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” |
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android:orientation=”vertical” |
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android:layout_width=”fill_parent” |
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android:layout_height=”fill_parent” |
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< Button android:id=”@+id/btn”
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android:layout_width=”wrap_content” |
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android:layout_height=”wrap_content” |
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android:text=”@string/mybtn” |
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android:background=”@drawable/mybutton_background” /> |
这种方式开发比较简单,适合做一些风格一致的Button,设置成同一个background就可以了。ImageView等控件如方法一中所述。
一般情况代码实现方式,有多个分辨率会报错java.lang.IllegalAccessError: tried to access field android.view.View.PRESSED_ENABLED_STATE_SET from class