Java 数据未通过android应用程序插入mysql数据库

我是android新手，当我试图从中插入数据时 我的android应用程序连接到localhost MySQL数据库，应用程序将自动终止。 MainActivity.java

public class MainActivity extends Activity

{

EditText ET_id,ET_FIRSTPLACE,ET_SECONDPLACE,ET_DISTANCE,ET_TIME2REACH,ET_FARE;
Button BT_SUBMIT;
String id,firstplace,secondplace,distance,time2reach,fare;

@Override
protected void onCreate(Bundle savedInstanceState)

{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ET_id=(EditText)findViewById(R.id.id);
    ET_FIRSTPLACE=(EditText)findViewById(R.id.firstplace);
    ET_SECONDPLACE=(EditText)findViewById(R.id.secondplace);
    ET_DISTANCE=(EditText)findViewById(R.id.distance);
    ET_TIME2REACH=(EditText)findViewById(R.id.time2reach);
    ET_FARE=(EditText)findViewById(R.id.fare);
    BT_SUBMIT=(Button)findViewById(R.id.submit);

}

public  void submit(View view)


{
    id=ET_id.getText().toString();
    firstplace=ET_FIRSTPLACE.getText().toString();
    secondplace=ET_SECONDPLACE.getText().toString();
    distance =ET_DISTANCE.getText().toString();
    time2reach=ET_TIME2REACH.getText().toString();
    fare=ET_FARE.getText().toString();

     String method="submit";

    BackgroundTask backgroundTask= new BackgroundTask(this);
    backgroundTask.execute(method,id,firstplace,secondplace,distance,time2reach,fare);
   finish();
 }
}

BackgroundTask.java

/**
 * Created by Sumedh on 29/08/2015.
 */
public class BackgroundTask extends AsyncTask <String,Void,String> {

Context ctx;

BackgroundTask(Context ctx) {

    this.ctx = ctx;

}

protected String doInBackground(String... params)


{
    String reg_url = "http://10.0.3.2/busspotter/insert.php";

        String method=params[0];
        String id =params[1];
        String firstplace =params[2];
        String secondplace =params[3];
        String distance =params[4];
        String time2reach =params[5];
        String fare =params[6];
if(method.equals("submit")) {
try {
    URL url = new URL(reg_url);
HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();  
    httpURLConnection.setRequestMethod("POST");
    httpURLConnection.setDoOutput(true);
    //httpURLConnection.setDoInput(true);

    OutputStream outputStream = httpURLConnection.getOutputStream();
    BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));

    String data = URLEncoder.encode("id","UTF-8")+"="+URLEncoder.encode(id,"UTF-8")+"&"+
            URLEncoder.encode("firstplace","UTF-8")+"="+URLEncoder.encode(firstplace,"UTF-8")+"&"+
            URLEncoder.encode("secondplace","UTF-8")+"="+URLEncoder.encode(secondplace,"UTF-8")+"&"+
            URLEncoder.encode("distance","UTF-8")+"="+URLEncoder.encode(distance,"UTF-8")+"&"+
            URLEncoder.encode("time2reach","UTF-8")+"="+URLEncoder.encode(time2reach,"UTF-8")+"&"+
            URLEncoder.encode("fare","UTF-8")+"="+URLEncoder.encode(fare,"UTF-8");
    bufferedWriter.write(data);
    bufferedWriter.flush();
    bufferedWriter.close();
    outputStream.close();
    InputStream inputStream = httpURLConnection.getInputStream();
    inputStream.close();
    httpURLConnection.disconnect();
    return "Inserted Succesfully...";
 } catch (MalformedInputException e) {
    e.printStackTrace();

 } catch (IOException e) {
    e.printStackTrace();

 }
}
return null;

 }

protected void onProgressUpdate(Void... values) {
    super.onProgressUpdate(values);
}

@Override
protected void onPostExecute(String result) {

        if (result.equals("Inserted Succesfully...")) {
            Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();

        }
    }
}

你的

方法返回null，并且您的onPostExecuteString结果尝试从null对象读取值

试着加上这个

if (result != null && result.equals("Inserted Succesfully...")) {
        Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();

    } else Toast.makeText(ctx, "Something went wrong", Toast.LENGTH_LONG).show();

---

您的android在发送http请求时是否连接到wifi？由于您似乎是在一个私人局域网地址上发出请求。我尝试了您的解决方案，但不起作用，应用程序显示出一些问题并被终止。

protected String doInBackground(String... params)

if (result != null && result.equals("Inserted Succesfully...")) {
        Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();

    } else Toast.makeText(ctx, "Something went wrong", Toast.LENGTH_LONG).show();