Anomaly with "Back" button when <min-sdk> used

I have encountered a very strange effect as I get near to finishing my project. I introduced the line

<uses-sdk android:minSdkVersion="8" />

into the manifest and re-ran the project in both the emulator and a phone (HTC Desire). I noticed that the "back" button wasn't operating in a number of areas of the program. When I put the code into debug, the onKeyDown listener was firing OK [and handed off ok to super.onKeyDown(..)] whereas the onBackPressed listener wasn't firing at all.

When I removed the uses-sdk entry from the manifest all returned to normal. Can anyone explain please because I really need to use the min-sdk statement.

Update: I have experimented right down to min-sdk="1开发者_开发知识库" (the default value) and the effect is the same. I then removed the min-sdk value and used the target-sdk value instead with EXACTLY THE SAME consequences i.e. the back button won't work in all places. Simply removing the tag <uses-sdk .... /> completely fixes the effect but leaves me with the problem of needing to declare a minimum sdk value before I deploy. Please help, someone, anybody...

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Maybe we met the same problem. I use this way to simulate a soft back button, but when "min-sdk" is added, the button doesn't work. It seems like "dispatchKeyEvent" and "min-sdk" are in conflict. I used "onBackPressed" instead, it works fine for me.

public class BackButtonClickListener implements View.OnClickListener {
    public void onClick(View v) {
        Activity host = (Activity) v.getRootView().getContext();
        host.onBackPressed();
    }
} 
Button back = (Button) findViewById(R.id.your_button_id);
back.setOnClickListener(new BackButtonClickListener());

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Why not use onKeyDown?

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
  if (keyCode == KeyEvent.KEYCODE_BACK) {
    // do some stuff
    return true;
  }
  return super.onKeyDown(keyCode, event);
}