安卓开发学习新手学习笔记笔记

1. 固定app仅竖屏
2. 获取app的版本号
3. 简单轮播图的实现

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1. 固定app仅竖屏

在AndroidManifest.xml里的活动注册里添加android:screenOrientation=“portrait”，如下：

<activity android:name=".mvp.ui.activity.AboutActivity"
            android:screenOrientation="portrait" ></activity>

2.获取app的版本号

 public static String packageName(Context context) {
        PackageManager manager = context.getPackageManager();
        String name = null;
        try {
            PackageInfo info = manager.getPackageInfo(context.getPackageName(), 0);
            name = info.versionName;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }

        return name;
    }

3.简单轮播图的实现

（1）build.gradle中添加依赖

    implementation 'com.github.bumptech.glide:glide:3.7.0'
    implementation 'com.youth.banner:banner:1.4.10'

（2）布局文件

<com.youth.banner.Banner
        android:id="@+id/banner"
        android:layout_width="match_parent"
        android:layout_height="300dp"/>

（3）图片加载器

public class GlideImageLoader extends ImageLoader {
    @Override
    public void displayImage(Context context, Object path, ImageView imageView) {

        Glide.with(context).load(path).into(imageView);

    }
}

（4）Activity活动

public class MainActivity extends AppCompatActivity {

    List<Integer> arrayList = new ArrayList();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        arrayList.add(R.drawable.aa);
        arrayList.add(R.drawable.bb);
        arrayList.add(R.drawable.cc);
        Banner banner = (Banner) findViewById(R.id.banner);
        banner.setImages(arrayList).setImageLoader(new GlideImageLoader()).start();
    }

}