Android-指示器-MagicIndicator的使用

1、要导入代码或引用包

compile project(':magicindicator')

repositories {
    ...
    maven {
        url "https://jitpack.io"
    }
}

dependencies {
    ...
    compile 'com.github.hackware1993:MagicIndicator:1.5.0'
}

2、如果使用指示器和ViewPage结合使用，则先建一个枚举保存频道

public enum CHANNEL {

  MY("我的", 0x01),

  DISCORY("发现", 0x02),

  FRIEND("朋友", 0x03),

  VIDEO("视频", 0x04);

  //所有类型标识
  public static final int MINE_ID = 0x01;
  public static final int DISCORY_ID = 0x02;
  public static final int FRIEND_ID = 0x03;
  public static final int VIDEO_ID = 0x04;

  private final String key;
  private final int value;

  CHANNEL(String key, int value) {
    this.key = key;
    this.value = value;
  }

  public int getValue() {
    return value;
  }

  public String getKey() {
    return key;
  }
}

3、使用数组保存频道值

    private static final CHANNEL[] CHANNELS =
            new CHANNEL[]{CHANNEL.MY, CHANNEL.DISCORY, CHANNEL.FRIEND};

4、添加带颜色渐变和缩放的指示器标题的ScaleTransitionPagerTitleView
ScaleTransitionPagerTitleView.java

import android.content.Context;

import net.lucode.hackware.magicindicator.buildins.commonnavigator.titles.ColorTransitionPagerTitleView;

/**
 * 带颜色渐变和缩放的指示器标题
 * 博客: http://hackware.lucode.net
 * Created by hackware on 2016/6/26.
 */
public class ScaleTransitionPagerTitleView extends ColorTransitionPagerTitleView {
    private float mMinScale = 0.9f;

    public ScaleTransitionPagerTitleView(Context context) {
        super(context);
    }

    @Override
    public void onEnter(int index, int totalCount, float enterPercent, boolean leftToRight) {
        super.onEnter(index, totalCount, enterPercent, leftToRight);    // 实现颜色渐变
        setScaleX(mMinScale + (1.0f - mMinScale) * enterPercent);
        setScaleY(mMinScale + (1.0f - mMinScale) * enterPercent);
    }

    @Override
    public void onLeave(int index, int totalCount, float leavePercent, boolean leftToRight) {
        super.onLeave(index, totalCount, leavePercent, leftToRight);    // 实现颜色渐变
        setScaleX(1.0f + (mMinScale - 1.0f) * leavePercent);
        setScaleY(1.0f + (mMinScale - 1.0f) * leavePercent);
    }

    public float getMinScale() {
        return mMinScale;
    }

    public void setMinScale(float minScale) {
        mMinScale = minScale;
    }
}

5、初始化指示器

initMagicIndicator();

    private void initMagicIndicator() {
        MagicIndicator magicIndicator = findViewById(R.id.magic_indicator);
        magicIndicator.setBackgroundColor(Color.WHITE);
        CommonNavigator commonNavigator = new CommonNavigator(this);
        commonNavigator.setAdjustMode(true);
        commonNavigator.setAdapter(new CommonNavigatorAdapter() {
            @Override
            public int getCount() {
                return CHANNELS == null ? 0 : CHANNELS.length;
            }

            @Override
            public IPagerTitleView getTitleView(Context context, final int index) {
                SimplePagerTitleView simplePagerTitleView = new ScaleTransitionPagerTitleView(context);
                simplePagerTitleView.setText(CHANNELS[index].getKey());
                simplePagerTitleView.setTextSize(19);
                simplePagerTitleView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
                simplePagerTitleView.setNormalColor(Color.parseColor("#999999"));
                simplePagerTitleView.setSelectedColor(Color.parseColor("#333333"));
                simplePagerTitleView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        mViewPager.setCurrentItem(index);
                    }
                });
                return simplePagerTitleView;
            }

            @Override
            public IPagerIndicator getIndicator(Context context) {
                return null;
            }

            @Override
            public float getTitleWeight(Context context, int index) {
                return 1.0f;
            }
        });
        magicIndicator.setNavigator(commonNavigator);
        ViewPagerHelper.bind(magicIndicator, mViewPager);
    }

6、编写ViewPage适配器
继承FragmentPagerAdapter 还是FragmentStatePagerAdapter
应先考虑页面数是否超过3页，超过用后者。

/**
 * 首页ViewPage适配器
 */
public class HomePagerAdapter extends FragmentPagerAdapter {

    private CHANNEL[] mList;

    public HomePagerAdapter(FragmentManager fm, CHANNEL[] datas) {
        super(fm);
        mList = datas;
    }

    //这种方式，避免一次性创建所有的framgent
    @Override
    public Fragment getItem(int position) {
        int type = mList[position].getValue();
        switch (type) {
            case CHANNEL.MINE_ID:
                return MineFragment.newInstance();
            case CHANNEL.DISCOVERY_ID:
                return DiscoryFragment.newInstance();
            case CHANNEL.FRIEND_ID:
                return FriendFragment.newInstance();
//            case CHANNEL.VIDEO_ID:
//                return VideoFragment.newInstance();
        }
        return null;
    }

    @Override
    public int getCount() {
        return mList == null ? 0 : mList.length;
    }
}

7、ViewPage初始化

        mViewPager = findViewById(R.id.view_pager);
        mAdapter = new HomePagerAdapter(getSupportFragmentManager(),CHANNELS);
        mViewPager.setAdapter(mAdapter);
        initMagicIndicator();