Asynctaskを使用して外部サイトからデータを取得する

Question

AsynctaskとJSonを初めて使用しました。

このサイトから通貨レートを取得する方法を知っていますか？

http://api.fixer.io/latest?base=SGD

、検索速度から

AsyncTask Android example

..私はこの記事を見てなかったけど、起動する方法をあまりにもわからないんだけど、私はに値を追加したいですこのListViewでは、カスタムListViewアダプタクラスを使用します。 MainActivity.classのためのXMLファイルの

コードが

<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="0.0dp" 
    android:orientation="horizontal" 
    android:layout_weight="0.4" 
    android:weightSum="1" > 

    <LinearLayout 
     android:layout_width="0.0dp" 
     android:layout_height="match_parent" 
     android:orientation="vertical" 
     android:layout_weight="0.8" > 

     <TextView 
      android:id="@+id/convertedAmtTV" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="0.00" 
      android:textSize="70dp" 
      android:gravity="right" /> 

     <EditText 
      android:id="@+id/inputAmtET" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="0" 
      android:textAlignment="textEnd" /> 

    </LinearLayout> 

    <LinearLayout 
     android:layout_width="0.0dp" 
     android:layout_height="match_parent" 
     android:orientation="vertical" 
     android:layout_weight="0.2"> 

     <TextView 
      android:id="@+id/convertedCurrTV" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="SGD" 
      android:textSize="28dp" 
      android:paddingLeft="2dp" 
      android:paddingTop="29dp" 
      android:paddingBottom="19dp" 
      android:gravity="center_horizontal" /> 

     <TextView 
      android:id="@+id/inputCurrTV" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:text="AUD" 
      android:textSize="28dp" 
      android:paddingLeft="2dp" 
      android:layout_marginTop="3dp" 
      android:gravity="center_horizontal" /> 

    </LinearLayout> 

</LinearLayout> 

<LinearLayout 
    android:orientation="vertical" 
    android:layout_weight="0.6" 
    android:layout_width="match_parent" 
    android:layout_height="0.0dp"> 

    <TextView 
     android:text="From" 
     android:textSize="21dp" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" /> 

    <ListView 
     android:id="@+id/currencyLV" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" /> 

</LinearLayout> 

コード

public class MainActivity extends AppCompatActivity { 

CurrencyRatesDetails crd = new CurrencyRatesDetails(); 

CurrencyRates cr = new CurrencyRates(); 

TextView inputCurrTV, convertedAmtTV; 
ListView currencyLV; 
EditText inputAmtET; 
ArrayAdapter<String> adapter; 
String[] currNameArr = crd.getNames(); 
String[] currCodeArr = crd.getCodes(); 
String[] currRateArr = crd.getRates(); 

String[] dbName; 
String[] dbCode; 
String[] dbRate; 

Context context; 

int index = 0; 

//String[] rateCurrArr = {"AUD", "BGN", "BRL", "CAD", "CHF", "CNY"}; 
//double[] rateArr = {0.944, 1.2824, 2.2842, 0.96158, 0.70946, 4.8624} 
Menu myMenu = null; 

double amtInput, finalConversion; 

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


    context = this; 
    //context.deleteDatabase("currency.db"); 

    inputAmtET = (EditText) findViewById(R.id.inputAmtET); 
    convertedAmtTV = (TextView) findViewById(R.id.convertedAmtTV); 
    inputCurrTV = (TextView) findViewById(R.id.inputCurrTV); 
    currencyLV = (ListView) findViewById(R.id.currencyLV); 

    /*for (int i = 0; i < currNameArr.length; i++) { 
     cr.addToDataBase(currNameArr[i], currCodeArr[i], currRateArr[i], getApplicationContext()); 
    }*/ 

    //cr.addToDataBase(currNameArr, getApplicationContext()); 

    //Resources myRes = this.getResources(); 
    //currArr = myRes.getStringArray(R.array.currencyList); 
    //adapter = ArrayAdapter.createFromResource(this, R.array.currencyList, android.R.layout.simple_selectable_list_item); 
    //adapter = new ArrayAdapter<String>(this, android.R.layout.simple_selectable_list_item, currNameArr); 
    //currencyLV.setAdapter(adapter); 

    dbName = cr.retrieveAllName(getApplicationContext()); 
    dbCode = cr.retrieveAllCode(getApplicationContext()); 
    dbRate = cr.retrieveAllRate(getApplicationContext()); 

    currencyLV.setAdapter(new CustomAdapter(this, dbName, dbCode, dbRate)); 

    currencyLV.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) { 

      inputCurrTV.setText(dbCode[i]); 

      index = i; 

      //Getting rate based on selected currency code 
      //rate = rateArr[i]; 

     } 
    }); 
} 

public boolean onCreateOptionsMenu(Menu menu) { 
    super.onCreateOptionsMenu(menu); 
    this.myMenu = menu; 
    addMenuItems(menu); 

    getMenuInflater().inflate(R.menu.mainmenu, menu); 
    return true; 
} 

private void addMenuItems(Menu menu) { 
    int index = 200; 
    menu.add(index, index, index, "Settings"); 
    menu.add(index, index + 1, index + 1, "Add Custom Rate"); 
    menu.add(index, index + 2, index + 2, "Load Default Rates"); 
} 

public boolean onOptionsItemSelected(MenuItem item) { 

    //getOrder() to get Menu Item at this specific orderId 
    if (item.getItemId() == R.id.menu_convert) { 

     amtInput = Double.parseDouble(inputAmtET.getText().toString()); 

     //finalConversion = amtInput/rate; 

     finalConversion = crd.conversion(amtInput, index); 

     //Formatting converted value to 2d.p 
     String finalValue = String.format("%.2f", finalConversion); 

     convertedAmtTV.setText(finalValue); 

    } else if (item.getItemId() == 201) { 

     Intent myIntent = new Intent(MainActivity.this, CustomXchangeRate.class); 
     startActivity(myIntent); 

    } 

    return true; 
} 

} 

カスタムListViewコントロールアダプタクラス

public class CustomAdapter extends BaseAdapter{ 

String[] resultNames; 
String[] resultCodes; 
String[] resultRates; 

Context context; 

private static LayoutInflater inflater = null; 

public CustomAdapter(CustomXchangeRate customXchangeRate, String[] names, String[] codes, String[] rates) { 
    resultNames = names; 
    resultCodes = codes; 
    resultRates = rates; 

    context = customXchangeRate; 

    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
} 

public CustomAdapter(MainActivity mainActivity, String[] names, String[] codes, String[] rates) { 
    resultNames = names; 
    resultCodes = codes; 
    resultRates = rates; 

    context = mainActivity; 

    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
} 

@Override 
public int getCount() { 
    return resultNames.length; 
} 

@Override 
public Object getItem(int position) { 
    return position; 
} 

@Override 
public long getItemId(int position) { 
    return position; 
} 

public class ViewHolder{ 
    TextView tvName; 
    TextView tvCode; 
    TextView tvRate; 
} 

@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 

    ViewHolder vh = new ViewHolder(); 
    View rowView; 

    rowView = inflater.inflate(R.layout.activity_custom_adapter, null); 

    vh.tvName = (TextView) rowView.findViewById(R.id.currencyNameTV); 
    vh.tvCode = (TextView) rowView.findViewById(R.id.currencyCodeTV); 
    vh.tvRate = (TextView) rowView.findViewById(R.id.currencyRateTV); 

    vh.tvName.setText(resultNames[position]); 
    vh.tvCode.setText(resultCodes[position]); 
    vh.tvRate.setText(resultRates[position]); 

    return rowView; 

} 
} 

ウルアプリ内でこのJSONを取得するための最良の方法は、バレーボールを使用するようになります任意の助け...

Answer 1

をお願い申し上げ：

https://developer.android.com/training/volley/simple.html

このリンクをチェックしてくださいあなたはウルが求めて見つけるでしょう。

乾杯