Question

我在我的应用程序中尝试移动到此活动时收到错误，应用程序崩溃时出现以下错误。这是这个活动的问题，还是我没有正确地创建子类。

过程：，PID：14746 java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.audiotest / com.example.audiotest.medical_record}：java.lang.NullPointerException：尝试调用虚方法'java.lang.String android.os.Bundle。 null对象引用上的getString（java.lang.String）'

public class medical_record extends Npatient实现AdapterView.OnItemSelectedListener {

private DatabaseReference mDatabase;
Spinner HyperTension;
private String selectht;
ArrayAdapter adapter;

private Button bHistory;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Bundle bundle =getIntent().getExtras();

    final String firebasechild=bundle.getString("child");
    mDatabase = FirebaseDatabase.getInstance().getReference();

    HyperTension = (Spinner) findViewById(R.id.shypertension);
    bHistory = (Button) findViewById(R.id.bHistory);

    adapter =ArrayAdapter.createFromResource(this,R.array.History, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    HyperTension.setAdapter(adapter);
    HyperTension.setOnItemSelectedListener(medical_record.this);

    bHistory.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            history hypertension = new history(selectht);
            mDatabase.child(firebasechild).push().setValue(hypertension);

            finish();
        }
    });



}

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    TextView SpinnerDialogText = (TextView) view;
    selectht = SpinnerDialogText.getText().toString();
    Toast.makeText(this, "you selected " + SpinnerDialogText.getText(), Toast.LENGTH_SHORT  ).show();

}

@Override
public void onNothingSelected(AdapterView<?> parent) {

}

}

Answer 1

打开此活动时，您是否传递任何额外内容？就像下面的例子一样：

Intent intent = new Intent(getBaseContext(), YourActivity.class);
intent.putExtra("child", "firebase child string");
startActivity(intent);

从基础活动转向扩展活动

1 个答案: