Question

我在片段类中有一个listview。单击列表视图项时，将打开另一个活动。该活动的xml文件在滚动视图中有2个图像视图。图像随点击的每个列表视图项而变化。我的应用中有5个列表视图。每个列表视图都有400多个项目。使用什么方法使其顺利运行。 switch语句是个好主意吗？目前我正在使用switch语句，到目前为止只有4个项目。我应该采用这种方法吗？

我的代码

public class urdufrag1 extends Fragment {

public urdufrag1() {
    // Required empty public constructor
}

public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);

}

private static final String TAG = "urdufrag1";

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup 
main_content, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.geetfrag_urdu, main_content, false);



     final int[] menuImage = {R.drawable.tgeet94, 
     R.drawable.tgeet95,R.drawable.tgeet96,R.drawable.tgeet97};
    final ListView listView = (ListView) view.findViewById(R.id.GeetListU);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
          Intent intent = new Intent(getActivity(), PackageG.class);
            intent.putExtra("position", position);
            startActivity(intent);

        }
    });
    AdapterGeetUrdu adapter = new AdapterGeetUrdu(getContext(), menuImage);
    listView.setAdapter(adapter);

    // Inflate the layout for this fragment



    return view;
}

}

第二项活动

public class PackageG extends AppCompatActivity {

ImageView img1, img2;
PhotoViewAttacher mAttacher;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_package_g);

    img1 = (ImageView) findViewById(R.id.imageView8);
    img2 = (ImageView) findViewById(R.id.imageView9);
    mAttacher = new PhotoViewAttacher(img1);
    mAttacher = new PhotoViewAttacher(img2);

    Intent intent = this.getIntent();
    if(intent != null){
        Integer position = intent.getExtras().getInt("position");

        switch (position){

            case 0: img1.setImageResource(R.drawable.geet94);
                    img2.setImageResource(R.drawable.geet94_1);
                break;
            case 1: img1.setImageResource(R.drawable.geet95);
                    img2.setImageResource(R.drawable.geet95_1);
                break;
            case 2: img1.setImageResource(R.drawable.geet96);
                    img2.setImageResource(R.drawable.geet96_1);
                break;

            default:
                img1.setImageResource(R.drawable.carol);
                img2.setImageResource(R.drawable.carol);
                break;

        }

    }

    mAttacher.update();

}

}

My list view

Second Activity

Answer 1

这是TypedArray的完美工作。使用类似

的文件创建文件res/values/arrays.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<array name="firstImages">
    <item>@drawable/R.drawable.geet94</item>
    <item>@drawable/R.drawable.geet95</item>
    <item>@drawable/R.drawable.geet96</item>
    ...
</array>
<array name="secondImages">
    <item>@drawable/R.drawable.geet94_1</item>
    <item>@drawable/R.drawable.geet95_1</item>
    <item>@drawable/R.drawable.geet96_1</item>
    ...
</array>
</resources>

然后在你的第二个活动中：

Intent intent = this.getIntent();
if(intent != null){
    Integer position = intent.getExtras().getInt("position");
    Resources res = getResources();

    TypedArray firstImages = res.obtainTypedArray(R.array.firstImages);
    TypedArray secondImages = res.obtainTypedArray(R.array.secondImages);

    Drawable firstDrawable = firstImages.getDrawable(position);
    Drawable secondDrawable = secondImages.getDrawable(position);

    img1.setImageDrawable(firstDrawable);
    img2.setImageDrawable(secondDrawable);
}

如何处理非常大的listview项目？通过switch语句或if / else语句？

1 个答案: