Question

我正在使TextView可单击，并希望在我点击它时更改文本。因此，TextView开始说“Al”，当它点击时我希望它改变说，现在就说“嗨”。然后再次单击时返回。这是我的代码。

package table.periodic;

import android.app.Activity; 
import android.content.Intent; 
import.os.Bundle; 
import android.view.ContextMenu; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 
import android.widget.TextView;

public class Aluminum extends Activity{
    public Button next; 
    public TextView symbol;   
    public static final int ONE_ID = Menu.FIRST+1; 
    public static final int TWO_ID = Menu.FIRST+2; 
    public static final int THREE_ID = Menu.FIRST+3;
    public static final int FOUR_ID = Menu.FIRST+4; 
    public static final int FIVE_ID = Menu.FIRST+5; public static
    final int SIX_ID = Menu.FIRST+6;

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.aluminum); 
        symbol = (TextView) findViewById(R.id.symbol);  

        symbol.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                symbol = (TextView) findViewById(R.id.symbol);
                if ("Al".equals(symbol.getText()));
                symbol.setText("Hi");
                if ("Hi".equals(symbol.getText()));
                symbol.setText("Al");

            }  });

        next = (Button) findViewById(R.id.next);

        next.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                Intent next = new Intent(Aluminum.this, Aluminum2.class);
                startActivity(next);}});
    }   
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo){
        populateMenu(menu);
    }

    public boolean onCreateOptionsMenu(Menu menu){
        populateMenu(menu);

        return(super.onCreateOptionsMenu(menu));

    }
    public boolean onOptionsItemSelected(MenuItem item){
        return(applyMenuChoice(item)||
                super.onOptionsItemSelected(item));

    }
    public boolean onContextItemSelected(MenuItem item){
        return(applyMenuChoice(item)||
                super.onContextItemSelected(item));
    }
    private void populateMenu(Menu menu){
        menu.add(Menu.NONE, ONE_ID, Menu.NONE, "Help");
        menu.add(Menu.NONE, TWO_ID, Menu.NONE, "Home");
        menu.add(Menu.NONE, THREE_ID, Menu.NONE, "List");
        menu.add(Menu.NONE, FOUR_ID, Menu.NONE, "Table");
    }

    private boolean applyMenuChoice(MenuItem item){
        switch (item.getItemId()){

        case ONE_ID:

            Intent help = new Intent(this, Help.class);
            startActivity(help);

            return(true);

        case TWO_ID:

            Intent table = new Intent(this, table.class);
            startActivity(table);

            return(true);

        case THREE_ID:

            Intent list = new Intent(this, List.class);
            startActivity(list);

            return(true);

        case FOUR_ID:
            Intent Classic = new Intent(this, Classic.class);
            startActivity(Classic);

            return(true);

        }   return false;
    }
}

Answer 1

您在点击侦听器中将符号设置为R.id.symbol。这会将其重置为XML文件中的内容。调用setText不会更改R.id.symbol中的值。 onclicklistener

中不需要symbol = (TextView) findViewById(R.id.symbol)

单击TextView和更改文本

1 个答案: