Question

我试图从主要活动转到第二个活动并传递一个数字而且它不起作用谁能证明我的错误是什么

P.S 任何人都可以告诉我如何做一个循环停止让用户按下按钮在EditText中添加文本，然后重置EditText并再次等待他插入另一个文本，直到数组填满

谢谢!!

public class MainActivity extends AppCompatActivity {

public static int numOfSails;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

try{
    Button nextButton = (Button) findViewById(R.id.next_button);
    EditText sailsNumET = (EditText) findViewById(R.id.sails_num);
    numOfSails = Integer.parseInt(sailsNumET.toString());
    nextButton.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view){
            Intent addingIntent = new Intent(MainActivity.this,AddingActivity.class);
            addingIntent.putExtra("nos",numOfSails);
            startActivity(addingIntent);

        }
    });


     }catch(NumberFormatException e){

  }
 }
}

并且在第二个活动中这是代码

public class AddingActivity extends AppCompatActivity {
public ArrayList<Sail> sails = new ArrayList<Sail>();
public static int numOfSails;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.adding_main);
    final Button addButton = (Button) findViewById(R.id.add_button);
    final EditText minusInGallonsET = (EditText) findViewById(R.id.gallons_num);
    final TextView counterET = (TextView) findViewById(R.id.counter_id);
    Bundle bundle = getIntent().getExtras();
    this.numOfSails = bundle.getInt("nos",0);
    for (int i = 0 ; i< numOfSails; i++){
        sails.add(new Sail());
    }

    addButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            int counter = 0;
            for (Sail s : sails){
                s.setFuelInGallons(Integer.parseInt(minusInGallonsET.toString()));
                s.setSailNum(counter);
                counter++;
                counterET.setText(counter);
            }
               }
    });

 }
}

Answer 1

请检查此代码在Xml文件

中

<EditText
    android:id="@+id/sails_num"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:inputType="number"/>

在活动文件

中

Button nextButton = (Button) findViewById(R.id.next_button);
        final EditText sailsNumET = (EditText) findViewById(R.id.sails_num);

        nextButton.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){
                final int numOfSails = Integer.parseInt(sailsNumET.getText().toString().equals("")?"0":sailsNumET.getText().toString());
                Intent addingIntent = new Intent(Main11Activity.this,AddingActivity.class);
                addingIntent.putExtra("nos",numOfSails);
                startActivity(addingIntent);

            }
        });

Answer 2

类似的东西：

public class SecondActivity extends AppCompatActivity {

    public void backToMain (View view) {
        Intent intent = new Intent(getApplicationContext(),MainActivity.class);
       intent.putExtra("ID", your_string);  //Heres what you want to pass. "ID" is needed to catch that given Intent on second activity
       startActivity(intent);
    }

}

还将onClickListener设置为按钮。：）

Answer 3

您正在存储由object.toString（）方法返回的字符串。哪个不会返回用户插入的值。

numOfSails = Integer.parseInt(sailsNumET.toString());

要获取用户插入的值，请使用以下代码。

numOfSails = Integer.parseInt(sailsNumET.getText().toString());

请注意，editText.getText（）返回一个Editable对象而不是字符串值，因此您必须使用toString（）方法。

为什么我的应用程序没有传递给下一个活动

3 个答案: