Android，java无法从asynctask更新变量

Question

这是密码

声明的变量

 public String gpu2dcurent = "1234567";

Asynctask，完成后应该更新变量gpu2dcurent，但它没有

 private class readgpu2d extends AsyncTask<String, Void, String> {


    protected String doInBackground(String... args) {
         Log.i("MyApp", "Background thread starting");

         String aBuffer = "";

         try {

            File myFile = new File("/sys/devices/platform/kgsl-2d0.0/kgsl/kgsl-2d0/gpuclk");
            FileInputStream fIn = new FileInputStream(myFile);
            BufferedReader myReader = new BufferedReader(
                    new InputStreamReader(fIn));
            String aDataRow = "";
            //String aBuffer = "";
            while ((aDataRow = myReader.readLine()) != null) {
                aBuffer += aDataRow + "\n";
            }

            ;
            myReader.close();

        } catch (Exception e) {
            Toast.makeText(getBaseContext(), e.getMessage(),
                    Toast.LENGTH_SHORT).show();

        }

         return aBuffer.trim();
     }

     protected void onPostExecute(String result) {
         // Pass the result data back to the main activity
        gpu2dcurent = result;
         //Toast.makeText(getBaseContext(), result,
                //Toast.LENGTH_SHORT).show();
         gpu.this.data = result;

         if (gpu.this.pd != null) {
             //gpu.this.pd.dismiss();
         }
     }

    }

测试变量是否有新值。它没有，它显示1234567

 TextView tx = (TextView)findViewById(R.id.textView3);
tx.setText(gpu2dcurent);

我错过什么了吗？当我从onPostExecute方法内部更新textView时，它工作正常，但当Asynctask完成时，变量值重置为默认值

 public class gpu extends Activity{

public String gpu2dcurent = "1234567";

Answer 1

尝试将setText放入onPostExecute

protected void onPostExecute(String result) {
     TextView tx = (TextView)findViewById(R.id.textView3);
     tx.setText(result);

     // Pass the result data back to the main activity
    gpu2dcurent = result;
     //Toast.makeText(getBaseContext(), result,
     //Toast.LENGTH_SHORT).show();
     gpu.this.data = result;

     if (gpu.this.pd != null) {
         //gpu.this.pd.dismiss();
     }
 }

Answer 2

在gpu类中声明如下：

public String gpu2dcurent = "1234567";

在AsyncTask类readgpu2d中，按如下方式使用它：

gpu.gpu2dcurent = result;

---

更新您的UI=用户界面意味着

onProgressUpdate（）

异步任务的方法

And check where have you declared gpu2dcurent variable???

Answer 3

这是全部代码

 package rs.pedjaapps.DualCore;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.util.List;
 import java.util.concurrent.TimeoutException;
 import android.app.Activity;
 import android.app.ProgressDialog;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
 import android.widget.Spinner;
 import android.widget.AdapterView.OnItemSelectedListener;
 import android.widget.TextView;
 import android.widget.Toast;

 import com.stericson.RootTools.RootTools;
 import com.stericson.RootTools.RootToolsException;

 public class gpu extends Activity{

public String gpu2dcurent = "1234567";

private ProgressDialog pd = null;
private Object data = null;

 private class readgpu2d extends AsyncTask<String, Void, String> {


    protected String doInBackground(String... args) {
         Log.i("MyApp", "Background thread starting");

         String aBuffer = "";

         try {

            File myFile = new File("/sys/devices/platform/kgsl-2d0.0/kgsl/kgsl-2d0/gpuclk");
            FileInputStream fIn = new FileInputStream(myFile);
            BufferedReader myReader = new BufferedReader(
                    new InputStreamReader(fIn));
            String aDataRow = "";
            //String aBuffer = "";
            while ((aDataRow = myReader.readLine()) != null) {
                aBuffer += aDataRow + "\n";
            }

            //gpu2dcurent = aBuffer.trim();
            myReader.close();




        } catch (Exception e) {
            Toast.makeText(getBaseContext(), e.getMessage(),
                    Toast.LENGTH_SHORT).show();

        }




         return aBuffer.trim();
     }

     protected void onPostExecute(String result) {
         // Pass the result data back to the main activity
        gpu2dcurent = result;
         //Toast.makeText(getBaseContext(), result,
                //Toast.LENGTH_SHORT).show();
         gpu.this.data = result;

         if (gpu.this.pd != null) {
             gpu.this.pd.dismiss();
         }

     }

    }




    @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gpu);
this.pd = ProgressDialog.show(this, "Working..", "Loading...", true, false);
new readgpu2d().execute("blablabla");
TextView tx = (TextView)findViewById(R.id.textView3);
tx.setText(gpu2dcurent);
 }


}

Answer 4

我怀疑您是否试图在完成任务之前设置TextView的文本

是的，要么去做，static public String gpu2dcurent = "1234567";

或者，在onPostExecute()中设置TextView的文本

protected void onPostExecute(String result) {
         // Pass the result data back to the main activity
        gpu2dcurent = result;
         //Toast.makeText(getBaseContext(), result,
                //Toast.LENGTH_SHORT).show();
         gpu.this.data = result;  
         if (gpu.this.pd != null) {
             //gpu.this.pd.dismiss();
         }
      tx.setText(gpu2dcurent);
     }
    }

更新：

更新相关代码后

换一行,

new readgpu2d().execute("blablabla");

到

new readgpu2d().execute("blablabla").get();