在onStart()中我想设置新值

时间:2015-06-27 16:27:01

标签: android android-activity forceclose activity-lifecycle onstart

public class MainActivity extends ActionBarActivity {



    Button b1;

    TextView tv2;

    Integer count ;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        count++;


        b1= (Button)findViewById(R.id.b1);
        tv2=(TextView)findViewById(R.id.tv2);

        tv2.setText(count);

        if(count == 5) {
            Intent ii = new Intent(this,Activity2.class );

            Bundle bb = new Bundle();

            bb.putInt("Count",count);

            ii.putExtras(bb);

            startActivity(ii);

            finish();

        }

        else

        {
            Intent iii = new Intent(this,activity3.class);

             // Bundle bb1 = new Bundle();

            startActivity(iii);
        }
    }

    public void onStart()
    {


        Bundle b33 = getIntent().getExtras();

        count=b33.getInt("count");

        tv2.setText(count);
    }

在这段代码中我想计算一个活动被打开的次数,在这种情况下,activity1将只打开5次,之后activity3将打开我尝试杀死activity1然后杀死我将计数值发送到activity2然后我再次调用activity1并再次将计数值发送到activity1,所以代码将从开始本身执行,所以再次值为1但我希望activity1在oncreate()或in中捕获count的新值onstart()

并且错误是应用程序未打开其强制关闭并且在logcat中显示Null-exception错误但是我执行了所有绑定。

1 个答案:

答案 0 :(得分:1)

在onStart()方法

上尝试此代码
public void onStart() 
{ 
Bundle b33 = getIntent().getExtras();
if(b33 != null)
{

    count=b33.getInt("count");

    tv2.setText(count);
}
} 

变化:

  

整数计数;

int count=0;

也改变了:

  

tv2.setText(计数);

to(在onCreate和onStart上):

tv2.setText(String.valueOf(count));

更新的代码:

public class MainActivity extends ActionBarActivity {



Button b1;

TextView tv2;

int count = 0 ;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    count++;


    b1= (Button)findViewById(R.id.b1);
    tv2=(TextView)findViewById(R.id.tv2);

    tv2.setText(String.ValueOf(count));

    if(count == 5) {
        Intent ii = new Intent(this,Activity2.class );

        Bundle bb = new Bundle();

        bb.putInt("Count",count);

        ii.putExtras(bb);

        startActivity(ii);

        finish();

    }

    else

    {
        Intent iii = new Intent(this,activity3.class);

         // Bundle bb1 = new Bundle();

        startActivity(iii);
    }
}

 public void onStart()
{
    super.onStart();
    Bundle b33 = getIntent().getExtras();
    if(b33 != null)
    {

        count=b33.getInt("count");

        tv2.setText(String.valueOf(count));
    }
}

我尝试了这段代码及其工作原理。