pass the value from activity to next activity in android

问题

I have developed one android application.

This is my first activity:

public class ViewCartActivity extends Activity {

String mGrandTotal;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.viewcartactivity);

    ListView mLstView1 = (ListView) findViewById(R.id.listView1);
    TextView mTxtViewGrandTotal = (TextView) findViewById(R.id.mTxtViewGrandTotalValue);
    Button mBtnSubmit = (Button) findViewById(R.id.mBtnSubmit);

    ViewCartAdapter mViewCartAdpt = new ViewCartAdapter(
            ViewCartActivity.this);

    mLstView1.setAdapter(mViewCartAdpt);

    if (Constants.mItem_Detail.size() > 0) {
        Double mGTotal = Double.parseDouble(Constants.mItem_Detail.get(0)
                .get(SingleMenuItem.KEY_TOTAL));
        for (int i = 1; i < Constants.mItem_Detail.size(); i++) {
            mGTotal = mGTotal
                    + Double.parseDouble(Constants.mItem_Detail.get(i).get(
                            SingleMenuItem.KEY_TOTAL));
        }

        mGrandTotal = String.valueOf(mGTotal);
        mTxtViewGrandTotal.setText("$" + mGrandTotal);
    }

    mBtnSubmit.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            String s= getIntent().getStringExtra(mGrandTotal);
             Intent i = new Intent(getApplicationContext(), CustomerLogin.class);
             i.putExtra("GrandTotal", s);
                startActivity(i);

        }
    });

This is my 2nd activity:

setContentView(R.layout.customer_login);

   Intent in = getIntent();
       String total = in.getStringExtra(mGrandTotal);
    TextView grandtotal = (TextView) findViewById(R.id.grand_total);
     grandtotal.setText("Welcome ,"+getIntent().getExtras().getString(total));

Here i have to run the app means am getting $45.32 on first activity. I have to pass these $45.32 to next activity means am getting null.

How can i clear these error.please help me how can i pass the value from 1st activity to next activity.

回答1:

FirstActivity

public class ViewCartActivity extends Activity {

String mGrandTotal;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.viewcartactivity);

    ListView mLstView1 = (ListView) findViewById(R.id.listView1);
    TextView mTxtViewGrandTotal = (TextView) findViewById(R.id.mTxtViewGrandTotalValue);
    Button mBtnSubmit = (Button) findViewById(R.id.mBtnSubmit);

    ViewCartAdapter mViewCartAdpt = new ViewCartAdapter(
            ViewCartActivity.this);

    mLstView1.setAdapter(mViewCartAdpt);

    if (Constants.mItem_Detail.size() > 0) {
        Double mGTotal = Double.parseDouble(Constants.mItem_Detail.get(0)
                .get(SingleMenuItem.KEY_TOTAL));
        for (int i = 1; i < Constants.mItem_Detail.size(); i++) {
            mGTotal = mGTotal
                    + Double.parseDouble(Constants.mItem_Detail.get(i).get(
                            SingleMenuItem.KEY_TOTAL));
        }

        mGrandTotal = String.valueOf(mGTotal);
        mTxtViewGrandTotal.setText("$" + mGrandTotal);
    }

    mBtnSubmit.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub


             Intent i = new Intent(getApplicationContext(), CustomerLogin.class);
             i.putExtra("GrandTotal", mGrandTotal);
                startActivity(i);

        }
    });


SecondActivity

setContentView(R.layout.customer_login);

  Bundle b = getIntent().getExtras();
       String total = b.getString("GrandTotal");
    TextView grandtotal = (TextView) findViewById(R.id.grand_total);
     grandtotal.setText("Welcome ," + total );

回答2:

change getIntent().getExtras().getString(total) To:

getIntent().getStringExtra("GrandTotal"); 

Or

String total = in.getStringExtra("GrandTotal");
grandtotal.setText("Welcome ," + total);

回答3:

Either store the value in shared preferences in one activity and get the value from same preference in another activity.

Storing in preferences

          SharedPreferences preferences=getSharedPreferences(preferencename, MODE_PRIVATE);
          Editor preferenceEditor=preferences.edit();

          preferenceEditor.putString(key,value);
          preferenceEditor.putInt(key,value);
          preferenceEditor.commit();

Getting from preferences

         preferences=getSharedPreferences(config_prop.getConfigValue("sharedprefs"), MODE_PRIVATE);
         String str=preferences.getString(key, defaultValue);

Also you can pass the values using intents.

回答4:

Just change

grandtotal.setText("Welcome ,"+getIntent().getExtras().getString(total));

to

grandtotal.setText("Welcome ,"getIntent().getExtras().getString(GrandTotal));

in second activity.

And remove

String s= getIntent().getStringExtra(mGrandTotal);

It should be

i.putExtra("GrandTotal", mGrandTotal);

from first activity on button click event. Because mGrandTotal is local activity variable. So you don't need to get it from intent

来源：https://stackoverflow.com/questions/13987269/pass-the-value-from-activity-to-next-activity-in-android