Android应用程序无法运行,应用程序已停止不幸。错误的代码在哪里?
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText edittext1 = (EditText) findViewById(R.id.editText1);
final Button button1 = (Button) findViewById(R.id.Button01);
final TextView tw = (TextView) findViewById(R.id.textView1);
final int valueint = Integer.parseInt(edittext1.getText().toString());
button1.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
tw.setText(Integer.toString(20*valueint));
}
});
}
代码是真的吗?
int valueint = Integer.parseInt(edittext1.getText().toString());
答案 0 :(得分:1)
您正在尝试在create上使用空int值。它可以在EditText中使用一些数字,但是当它为空时它必须崩溃。 tw.setText metod也错了。尝试此代码,工作:
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity1 extends Activity {
EditText edit;// = (EditText) findViewById(R.id.editText1);
Button button;// = (Button) findViewById(R.id.button1);
TextView tw;// = (TextView) findViewById(R.id.textView1);
int valueint;// = Integer.parseInt(edit.getText().toString());
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity1);
edit = (EditText) findViewById(R.id.editText1);
button = (Button) findViewById(R.id.button1);
tw = (TextView) findViewById(R.id.textView1);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
valueint = Integer.parseInt(edit.getText().toString());
tw.setText(String.valueOf(20 * valueint));
}
});
}