按钮状态--代码设定

      采用xml写出来的效果皆可以用代码来实现，下面的代码就是通过代码编写来实现view的状态的切换效果。

      public void setPressedBg(View view, Drawable normal,Drawable focused, Drawable pressed) {    StateListDrawable bg = new StateListDrawable();    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 ,android.R.attr.state_window_focused};              states[4] = new int[] { android.R.attr.state_window_focused };     bg.addState(states[0], pressed);    bg.addState(states[3], focused);    bg.addState(states[2], normal);   view.setBackgroundDrawable(bg);}