StateListDrawableBuilder.java

package com.imaygou.android.helper.drawable;

import android.graphics.drawable.Drawable;
import android.graphics.drawable.StateListDrawable;
import android.util.StateSet;

/**
 * Created by longkai on 20/1/15.
 */
public class StateListDrawableBuilder {
  private static final int   DEFAULT_CAPACITY = 2;

  public static final  int[] STATE_PRESSED    = new int[]{android.R.attr.state_pressed};

  private int        size;
  private int[][]    states;
  private Drawable[] drawables;

  public StateListDrawableBuilder() {
    this.states = new int[DEFAULT_CAPACITY][];
    this.drawables = new Drawable[DEFAULT_CAPACITY];
  }

  public StateListDrawableBuilder setStates(int[][] states) {
    this.states = states;
    this.size = states.length;
    return this;
  }

  public StateListDrawableBuilder setDrawables(Drawable[] drawables) {
    this.drawables = drawables;
    this.size = states.length;
    return this;
  }

  public StateListDrawableBuilder addState(int[] state, Drawable drawable) {
    if (size + 1 == states.length) {
      // expand the array
      int[][] tmpStates = new int[states.length + 2][]; // plus 2
      System.arraycopy(states, 0, tmpStates, 0, states.length);
      states = tmpStates;

      Drawable[] tmpDrawables = new Drawable[states.length];
      System.arraycopy(drawables, 0, tmpDrawables, 0, drawables.length);
      drawables = tmpDrawables;
    }
    states[size] = state;
    drawables[size] = drawable;
    size++;
    return this;
  }

  public StateListDrawableBuilder addPressedState(Drawable drawable) {
    return addState(STATE_PRESSED, drawable);
  }

  public StateListDrawableBuilder addDefaultState(Drawable drawable) {
    return addState(StateSet.WILD_CARD, drawable);
  }

  public StateListDrawable build() {
    if (states.length != drawables.length) {
      throw new IllegalArgumentException("states' length must equals drawables' length");
    }
    StateListDrawable listDrawable = new StateListDrawable();
    for (int i = 0; i < size; i++) {
      listDrawable.addState(states[i], drawables[i]);
    }
    return listDrawable;
  }
}