Question

给出示例数组

public class MainActivity extends AppCompatActivity  {

ImageView imgValue ;
Button btnDownload ;
EditText edtUrl ;

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

    imgValue = findViewById(R.id.imgValue);
    btnDownload = findViewById(R.id.btnDownload);
    edtUrl = findViewById(R.id.edtUrl);

    btnDownload.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            GetImage imageDownloader = new GetImage();
            imageDownloader.execute("https://upload.wikimedia.org/wikipedia/commons/d/d7/Android_robot.svg");
        }
    });


}
private class GetImage extends AsyncTask<String,Void,Bitmap>{

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected Bitmap doInBackground(String... strings) {

        Bitmap downloadedImage = null ;
        String theUrl = strings[0];
        try {
            URL url = new URL(theUrl);
            InputStream stream = url.openStream() ;
            downloadedImage = BitmapFactory.decodeStream(stream);

        }
        catch (Exception ex){
            ex.printStackTrace();

        }

        return downloadedImage ;
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        super.onPostExecute(bitmap);

        imgValue.setImageBitmap(bitmap);
        Toast.makeText(MainActivity.this, "ddd", Toast.LENGTH_SHORT).show();
    }
  }
}

在（普通）Js中，是否有可能有效地获得与两种给定颜色匹配的array = [ ["name1", ["blue", "yellow", "pink"], "id"], ["name2", ["green", "orange"], "id"], ["nameN", ["purple", "black", "white", "red"], "id"], ];和name（比如id和red）？

Answer 1

您可以使用Array#find方法根据条件获取特定元素，并可以使用Array#includes方法检查数组是否包含特定值。

let array = [
  ["name1", ["blue", "yellow", "pink"], "id"],
  ["name2", ["green", "orange"], "id"],
  ["nameN", ["purple", "black", "white", "red"], "id"],
];

let color = 'orange';

let [name, colors, id] = array.find(a => a[1].includes(color));

console.log(name, id)

Answer 2

您还可以使用 reduce ：

const arr = [
  ['name1', ['blue', 'yellow', 'pink'], 'id'],
  ['name2', ['green', 'orange'], 'id'],
  ['nameN', ['purple', 'black', 'white', 'red'], 'id'],
];

const getNameAndIdByColor = (color) =>
  arr.reduce(
    (acc, [name, colors, id]) => (colors.includes(color) ? { ...acc, [color]: { name, id } } : acc),
    {},
  );

console.log('getNameAndIdByColor:', getNameAndIdByColor('red'));

给定两个变量，在Js数组中搜索

2 个答案: