android - ViewPager OnPageChangeListener 不起作用

Question

我正在使用自定义 ViewPager，当我滑动到新页面时，ViewPager.OnPageChangeListener 不起作用。可能是什么原因？

mPager = (WrapContentHeightViewPager) findViewById(R.id.pager);

mPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    public void onPageScrollStateChanged(int state) {}
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

    public void onPageSelected(int position) {
        // Check if this is the page you want.
        currentFav = position;
        Log.i("currentFav pos", currentFav+"");
    }
});

Answer 1

我正在使用 ViewPagerIndicator 库，所以根据这个库，我应该在指示器上设置页面监听器。

mIndicator.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            doYourThing();
        }
    });

@powder366 的更新:

在您的 build.gradle 文件中，将库添加到依赖项中

compile 'com.viewpagerindicator:library:2.4.1@aar'

在您的顶级 build.gradle 文件中，添加以下内容:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        maven { url "http://dl.bintray.com/populov/maven" }
        mavenCentral()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven { url "http://dl.bintray.com/populov/maven" }
        mavenCentral()
        jcenter()
    }
}

您可以将指示器添加到您的 xml 中，如下所示:

 <com.viewpagerindicator.CirclePageIndicator
                            android:id="@+id/indicator"
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:background="@color/blue"
                            android:padding="10dip"
                            app:fillColor="@color/circleindicatorfill"
                            app:pageColor="@color/circleindicatorempty"
                            app:strokeWidth="0dp" />

获取指标如下:

mIndicator = (CirclePageIndicator) findViewById(R.id.indicator);

mViewPager.setAdapter(mFragmentAdapter);

mIndicator.setViewPager(mViewPager);

mIndicator
         .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
                    public void onPageScrollStateChanged(int state) {
                    }

                    public void onPageScrolled(int position,
                                               float positionOffset, int positionOffsetPixels) {
                    }

                    public void onPageSelected(int position) {

                        // Check if this is the page you want.
                       /* currentFav = position;
                        Log.i("currentFav pos", currentFav + "");*/
                    }
                });