Android - 如何检查 textview 是否为 null 或不为 null

Question

我的应用程序中有一些 TextView 并想检查我的 TextView 上文本的属性是否有值或为空。然后如果我的 textview 上的值为空，我想显示 toast

但是 toast 没有正常运行

这是我的代码:

public class brekeleV2 extends Activity {
static Context context;
brekeleV2Model r = new brekeleV2Model();
private EditText jalan, kota, postal;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    context = getApplicationContext();
    Button go = (Button)findViewById(R.id.go);
    go.setOnClickListener(onGo);

    Button reset = (Button)findViewById(R.id.reset);
    reset.setOnClickListener(onRes);
    jalan =(EditText)findViewById(R.id.jalan);
    kota =(EditText)findViewById(R.id.kota);
    postal =(EditText)findViewById(R.id.post);
    jalan.setText(null);
    kota.setText(null);
    postal.setText(null);
}

这是 onClick 方法代码:

private View.OnClickListener onGo=new View.OnClickListener() {

    public void onClick(View v) {
        if (jalan.getText()!= null && kota.getText()!=null){
            switch(v.getId()){
                case R.id.go:
                    Intent maps = new Intent();
                    maps.setClassName("com.openit.brekele", "com.openit.brekele.brekeleV2Nav");
                    brekeleV2Nav.putLatLong(lat, lon);
                    startActivity(maps);
                    break;

            }
        }else{
            Toast msg = Toast.makeText(brekeleV2.this, "Lengkapi Data", Toast.LENGTH_LONG);
            msg.setGravity(Gravity.CENTER, msg.getXOffset() / 2, msg.getYOffset() / 2);
            msg.show();
        }

Answer 1

if(!textview.getText().toString.matches(""))
{
    // not null not empty
}else {
    //null or empty
}