Question

03-05 11：31：07.042 1897-1897 / com.example.project.a D / AndroidRuntime：关闭VM       ---------崩溃的开始   03-05 11：31：07.050 1897-1897 / com.example.project.a E / AndroidRuntime：FATAL

例外：主要       处理：com.example.project.a，PID：1897       java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.project.a / com.example.project.a.MainActivity}：java.lang.NullPointerException：尝试调用虚方法＆＃39; void android.widget .LinearLayout.removeAllViews（）＆＃39;在null对象引用上               在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2298）               在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2360）

public void onItemSelected（AdapterView arg0，View arg1，int arg2，long arg3）{

        //   Toast.makeText(getApplicationContext(),"The day qqq"+arg0.getItemAtPosition(arg2).toString(),Toast.LENGTH_LONG).show();
        String control2=arg0.getItemAtPosition(arg2).toString();

       int  noOfBulb= (int) spinner1.getSelectedItem();
        final TextView tryText2=(TextView)findViewById(R.id.textView);
        tryText2.setText("No"+noOfBulb);

        mdynamiclayout = (LinearLayout) findViewById(R.id.dynamiclayout);
        mdynamiclayout.removeAllViews();//need to remove the view before it create
        for (int i = 0; i < noOfBulb; i++) {//6 is your selected item from spinner it can be any nymber
            TextView t = new TextView(MainActivity.this);
            t.setText("value" + i);
            //  t.setTextSize(20);
            //  t.setTextColor(Color.BLUE);
            mdynamiclayout.addView(t);
        }

    }

    public  void onNothingSelected(AdapterView<?> arg0){}

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


    rl = (RelativeLayout) findViewById(R.id.rl);

    tv1 = new TextView (MainActivity.this);


    tv1.setText("Dynamic TextView");


    tv1.setTextColor(Color.RED);


    tv1.setTextSize(20);


    RelativeLayout.LayoutParams params1=new RelativeLayout.LayoutParams
            ((int)LayoutParams.WRAP_CONTENT,(int)LayoutParams.WRAP_CONTENT);
    params1.leftMargin=115;
    params1.topMargin=120;



   rl.addView(tv1);

public class Unit {
    private  String  _bulbNo;

    public  Unit(String bulbNo) {

        _bulbNo = bulbNo;


    }
    public  String getBulbNo(){
        return  _bulbNo;
    }

}
// I created this class


 private  void addBulbsFans(String bulb)
    {
        Units.add(new Unit(bulb));
    }

//我将此方法添加到MainActivity.java。之后，我需要知道如何从buttonclick事件传递微调器值。

Answer 1

您可以通过以下

简单地将所选字符串转换为整数

 int value = Integer.valueOf(spiner.getselecteditem);

Answer 2

您使用Integer.valueOf()，在您的情况下就是这样：

String[] bulbs = {"0","1","2","3","4","5"};
Integer[] bulbsConvert = new Integer[6];
//Array to int
for(String item : bulbs){
   bulbsConvert.add(Integer.valueOf(item));
}

Answer 3

如果要以垂直顺序创建动态文本视图，请在xml中创建LinearLayout，并将方向设置为垂直，如下所示

  <LinearLayout
        android:id="@+id/dynamiclayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/registerlayout"
        android:layout_below="@+id/registerlayout"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="34dp"
        android:orientation="vertical" >
    </LinearLayout>

然后在您的活动中添加以下代码行

private LinearLayout mdynamiclayout;

mdynamiclayout = (LinearLayout) findViewById(R.id.dynamiclayout);

        mdynamiclayout.removeAllViews();//need to remove the view before it create
        for (int i = 0; i < 6; i++) {//6 is your selected item from spinner it can be any nymber
            TextView t = new TextView(MainActivity.this);
            t.setText("value" + i);
            mdynamiclayout.addView(t);
        }

将一项活动传递给另一项活动：

Intent intent_value = new Intent(Mainactivity.this,
                yoursecondactivity.class);
        intent_value.putExtra("key", value);
        intent_value.putExtra("key2", value2);
        startActivity(intent_value);

检索值：

 Intent getValues = getIntent();
    String value1 = getValues.getStringExtra("key");

如果您需要任何帮助，请告诉我

如何根据微调器中的选定整数创建动态文本视图？

3 个答案: