How can I solve this Intent problem?

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How can I solve this Intent problem?

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#1 by (1 votes)

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In my program I have two activity, the first one calls the second using Intent, the second one returns some String variables and returns to the first one also using Intent, the problem is that I have an error when starting the 1st activity because there is a bundle without data; although apparently it has no logic, this is just a piece of code to try to explain my problem. As I can solve this, it would be possible to indicate to the program that when starting for the first time do not call the bunde and after having called the 2nd activity already execute ...?

Here is my 1st activity

public class MainActivity extends AppCompatActivity {

private TextView mDumpTextView;
private ScrollView mScrollView;
private Button mBotonSend;
private EditText mTextoEditor1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_main );
    mBotonSend = (Button)findViewById( R.id.bt2_SendButton ) ;
    mDumpTextView = (TextView) findViewById(R.id.tv1_ReadValues);
    mScrollView = (ScrollView) findViewById(R.id.sc1_Scroller);
    mTextoEditor1 = (EditText)findViewById( R.id.et1_WriteValues );

    Bundle bundle = getIntent().getExtras();
    String textoImportado2=bundle.getString("texto2");
    mDumpTextView.setText(textoImportado2);

    mBotonSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(v.getContext(), PreferenceActivity.class);
            intent.putExtra("texto1", mTextoEditor1.getText().toString());
            mTextoEditor1.setText( "" );

            startActivityForResult(intent, 0);
        }
    });
}

}

And here is my 2nd activity

public class PreferenceActivity extends AppCompatActivity {
private TextView mDumpTextView;
private ScrollView mScrollView;
private EditText mTextoEditor1;
private Button mBotonSend;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_main2 );

    Bundle bundle = getIntent().getExtras();
    String textoImportado1=bundle.getString("texto1");

    mTextoEditor1 = (EditText)findViewById( R.id.et1_WriteValues );
    mBotonSend = (Button)findViewById( R.id.bt2_SendButton ) ;
    mScrollView = (ScrollView) findViewById(R.id.sc1_Scroller);
    TextView mDumpTextView = (TextView)findViewById(R.id.tv1_ReadValues);

    mDumpTextView.setText(textoImportado1);

    mBotonSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent2 = new Intent(v.getContext(), MainActivity.class);
            intent2.putExtra("texto2", mTextoEditor1.getText().toString());
            mTextoEditor1.setText( "" );
            startActivityForResult(intent2, 0);
        }
    });
}

}

android-intent

asked by W1ll 26.11.2018 в 19:37

source

1 answer

Data is lost in the Controller - View - Controller process Java Functional Methods

score 1 · Answer 1

If Activity starts without an Intent, then getIntent() returns null .

For the case you mention, in onCreate() you can do:

boolean tengoBundle = false;
Intent intent = getIntent();
Bundle extras = null;
if(intent != null){
   extras = intent.getExtras();
   tengoBundle = true;
}

The tengoBundle is optional, it is only imagining that there are parts of the code that should have a default behavior if there is no Bundle where to get the data and you can use this variable to determine the flow of the program.

Example:

String textoImportado2=""; //Default;
if(tengoBundle){
   textoImportado2 = bundle.getString("texto2");
}