android的ColorStateList简单使用

优点

灵活，减少xml的编写。应用在TextView的文字时，亦避免使用了OnTouchListener。

用途

动态设置TextView、Button、ImageView等组件在不同状态下的背景/前景显示效果。

代码

package lab.sodino.statelist;
 
import android.app.Activity;
import android.content.Context;
import android.content.res.ColorStateList;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.StateListDrawable;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
 
/**
 * 对TextView设置ColorStateList使其在Normal、Pressed、Focused、Unable四种状态下显示不同的颜色。<br/>
 * StateListDrawable可直接使用图片应用在相似场合。
 */
public class ActColorStateList extends Activity implements OnClickListener {
    private TextView txtShow;
 
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        txtShow = (TextView) findViewById(R.id.txtShow);
        txtShow.setText("Sodino\nNormal:0xffffffff\nPressed:0xffffff00\nFocused:0xff0000ff\nUnable:0xffff0000");
        txtShow.setTextColor(createColorStateList(0xffffffff, 0xffffff00, 0xff0000ff, 0xffff0000));
        txtShow.setOnClickListener(this);
    }
 
    /** 对TextView设置不同状态时其文字颜色。 */
    private ColorStateList createColorStateList(int normal, int pressed, int focused, int unable) {
        int[] colors = new int[] { pressed, focused, normal, focused, unable, normal };
        int[][] states = new int[6][];
        states[0] = new int[] { android.R.attr.state_pressed, android.R.attr.state_enabled };
        states[1] = new int[] { android.R.attr.state_enabled, android.R.attr.state_focused };
        states[2] = new int[] { android.R.attr.state_enabled };
        states[3] = new int[] { android.R.attr.state_focused };
        states[4] = new int[] { android.R.attr.state_window_focused };
        states[5] = new int[] {};
        ColorStateList colorList = new ColorStateList(states, colors);
        return colorList;
    }
 
    /** 设置Selector。 */
    public static StateListDrawable newSelector(Context context, int idNormal, int idPressed, int idFocused,
            int idUnable) {
        StateListDrawable bg = new StateListDrawable();
        Drawable normal = idNormal == -1 ? null : context.getResources().getDrawable(idNormal);
        Drawable pressed = idPressed == -1 ? null : context.getResources().getDrawable(idPressed);
        Drawable focused = idFocused == -1 ? null : context.getResources().getDrawable(idFocused);
        Drawable unable = idUnable == -1 ? null : context.getResources().getDrawable(idUnable);
        // View.PRESSED_ENABLED_STATE_SET
        bg.addState(new int[] { android.R.attr.state_pressed, android.R.attr.state_enabled }, pressed);
        // View.ENABLED_FOCUSED_STATE_SET
        bg.addState(new int[] { android.R.attr.state_enabled, android.R.attr.state_focused }, focused);
        // View.ENABLED_STATE_SET
        bg.addState(new int[] { android.R.attr.state_enabled }, normal);
        // View.FOCUSED_STATE_SET
        bg.addState(new int[] { android.R.attr.state_focused }, focused);
        // View.WINDOW_FOCUSED_STATE_SET
        bg.addState(new int[] { android.R.attr.state_window_focused }, unable);
        // View.EMPTY_STATE_SET
        bg.addState(new int[] {}, normal);
        return bg;
    }
 
    @Override
    public void onClick(View v) {
        if (v == txtShow) {
            txtShow.setEnabled(false);
        }
    }
}